Remove history from website and complete changelog.

No need to maintain 2 changelogs.
Besides, the actual changelog is behind the one on the website.
Just keep CHANGELOG.md updated and remove the other one.

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 3.5.1 - 2020-09-15
+### Changed
+- Fixed a bug in handling compiler options
+
 ## 3.5 - 2020-09-01
 - IBM System/390 support is added.
 - The library can be built with Clang on Windows.

doc/html/index.xhtml

@@ -383,117 +383,10 @@ information about Boost Software License.
 
 <h2 id="history">History</h2>
 
-<h4>3.5.1 (Released on Sep 15, 2020)</h4>
-<ul class="disc">
-  <li>Fixed a bug in handling compiler options</li>
-</ul>
-
-<h4>3.5 (Released on Sep 1, 2020)</h4>
-<ul class="disc">
-  <li>IBM System/390 support is added (PR <a class="underlined"
-  href="https://github.com/shibatch/sleef/pull/291">#291</a>)</li>
-  <li>The library can be built with Clang on Windows (PR <a class="underlined"
-  href="https://github.com/shibatch/sleef/pull/300">#300</a>)</li>
-  <li>Static libraries with LTO can be generated (PR
-    <a class="underlined" href="https://github.com/shibatch/sleef/pull/290">#290</a>)</li>
-  <li>Alternative division and sqrt methods can be chosen with AArch64 (PR
-    <a class="underlined" href="https://github.com/shibatch/sleef/pull/289">#289</a>)</li>
-  <li>Header files for inlining the whole SLEEF functions can be
-generated (PR <a class="underlined"
-href="https://github.com/shibatch/sleef/pull/283">#283</a>)</li>
-  <li>IEEE remainder function is added (PR
-    <a class="underlined" href="https://github.com/shibatch/sleef/pull/271">#271</a>)</li>
-  <li>GCC-10 can now build SLEEF with SVE support (PR
-    <a class="underlined" href="https://github.com/shibatch/sleef/pull/310">#310</a>)</li>
-</ul>
-
-<h4>3.4.1 (Released on Oct 1, 2019)</h4>
-<ul class="disc">
-  <li>Fixed accuracy problem with tan_u35, atan_u10, log2f_u35 and exp10f_u10 (PR
-    <a class="underlined" href="https://github.com/shibatch/sleef/pull/260">#260</a>,
-    <a class="underlined" href="https://github.com/shibatch/sleef/pull/265">#265</a>,
-    <a class="underlined" href="https://github.com/shibatch/sleef/pull/267">#267</a>)</li>
-  <li>SVE intrinsics that are not supported in newer ACLE are replaced (PR
-    <a class="underlined" href="https://github.com/shibatch/sleef/pull/268">#268</a>)</li>
-  <li>FMA4 detection problem is fixed (PR
-    <a class="underlined" href="https://github.com/shibatch/sleef/pull/262">#262</a>)</li>
-  <li>Compilation problem under Windows with MinGW is fixed (PR
-    <a class="underlined" href="https://github.com/shibatch/sleef/pull/266">#266</a>)</li>
-</ul>
-
-<h4>3.4 (Released on Apr 28, 2019)</h4>
-<ul class="disc">
-  <li>Faster and low precision functions are
-    added (PR <a class="underlined"
-		href="https://github.com/shibatch/sleef/pull/229">#229</a>)</li>
-  <li>Functions that return consistent results across platforms are
-    added (PR <a class="underlined" href="https://github.com/shibatch/sleef/pull/216">#216</a>,
-    <a class="underlined" href="https://github.com/shibatch/sleef/pull/224">#224</a>)</li>
-  <li>Many functions are now faster (PR <a class="underlined"
-    href="https://github.com/shibatch/sleef/pull/239">#239</a>)</li>
-  <li>Quad precision math library(libsleefquad) is added
-    (PR <a class="underlined" href="https://github.com/shibatch/sleef/pull/235">#235</a>,
-    <a class="underlined" href="https://github.com/shibatch/sleef/pull/237">#237</a>,
-    <a class="underlined" href="https://github.com/shibatch/sleef/pull/240">#240</a>)</li>
-  <li>Testers are now faster (PR <a class="underlined"
-    href="https://github.com/shibatch/sleef/pull/223">#223</a>)</li>
-</ul>
-
-<h4>3.3.1 (Released on Aug 21, 2018)</h4>
-<ul class="disc">
-  <li>i386 build problem is fixed</li>
-  <li>FreeBSD support is added</li>
-  <li>Trigonometric functions now evaluate correctly with full FP
-  domain. (PR <a class="underlined"
-  href="https://github.com/shibatch/sleef/pull/210">#210</a>)</li>
-</ul>
-
-<h4>3.3 (Released on July 6, 2018)</h4>
-<ul class="disc">
-  <li>AArch64 SVE target support is added (PR <a class="underlined"
-  href="https://github.com/shibatch/sleef/pull/180">#180</a>, <a class="underlined"
-  href="https://github.com/shibatch/sleef/pull/182">#182</a>)</li>
-  <li>DFT is now faster (PR <a class="underlined"
-  href="https://github.com/shibatch/sleef/pull/186">#186</a>)</li>
-  <li>3.5-ULP hyperbolic functions are added (PR <a class="underlined"
-  href="https://github.com/shibatch/sleef/pull/192">#192</a>)</li>
-  <li>PowerPC VSX target support is added (PR <a class="underlined"
-  href="https://github.com/shibatch/sleef/pull/195">#195</a>)</li>
-  <li>Modified Payne-Hanek argument reduction is added to the
-  trigonometric functions in libsleef (PR <a class="underlined"
-  href="https://github.com/shibatch/sleef/pull/197">#197</a>)</li>
-</ul>
-
-<h4>3.2 (Released on Feb 26, 2018)</h4>
-<ul class="disc">
-  <li>The whole build system of the project migrated from makefiles to
-  cmake. The makefile build system is now removed.</li>
-  <li>GNUABI version of the library with compatibility tests is
-  added.</li>
-  <li>Benchmarks that compare `libsleef` vs `SVML` on X86 Linux are
-  available in the project tree under src/libm-benchmarks
-  directory.</li>
-  <li>Extensive upstream testing via Travis CI and Appveyor</li>
-  <li>log2 is added.</li>
-  <li>The library can be compiled to an LLVM bitcode object</li>
-  <li>Added masked interface to the library to support AVX512F masked
-  vectorization.</li>
-  <li>Use native instructions if available for `sqrt`.</li>
-  <li>Removed `libm` dependency.</li>
-  <li>fmod(FP remainder), asin, acos, log, pow, log10, exp2, exp10 and
-  log1p functions are now faster.</li>
-  <li>Fixed a bug that was making the error of sinpi, cospi, sincospi,
-  and tgamma functions larger than the specifications on very rare
-    occasions.</li>
-  <li>Fixed a bug that was preventing the dispatcher from choosing the
-  FMA4 implementation.</li>
-</ul>
-
 <p class="noindent" style="margin-top: 1.0cm;">
 See <a class="underlined"
 href="https://github.com/shibatch/sleef/blob/master/CHANGELOG.md">Changelog</a>
-for older changes.</p>
-
+for a full history of changes to SLEEF.</p>
 
 <h2 id="related">Related projects and links</h2>