Update dependencies excluding Koa 2

[nickserv]

This updates most dependencies to the latest versions that have no requirement on Koa 2.

Fixes #34 and all of its listed deprecation warnings except for jshttp/spdy-push#5.

Excluded package updates

koa-body-parsers@^2.0.0

Recent versions of this middleware break the BodyParsing tests even though the middleware is Koa 2 compatible. There are either regressions in the middleware or API changes that we should support in Koala.

  1) Body Parsing .request.json() should parse a json body:
     Error: expected 200 "OK", got 500 "Internal Server Error"
      at Test._assertStatus (node_modules/supertest/lib/test.js:266:12)
      at Test._assertFunction (node_modules/supertest/lib/test.js:281:11)
      at Test.assert (node_modules/supertest/lib/test.js:171:18)
      at assert (node_modules/supertest/lib/test.js:131:12)
      at node_modules/supertest/lib/test.js:128:5
      at Test.Request.callback (node_modules/superagent/lib/node/index.js:631:3)
      at IncomingMessage.<anonymous> (node_modules/superagent/lib/node/index.js:795:18)
      at endReadableNT (_stream_readable.js:1059:12)
      at _combinedTickCallback (internal/process/next_tick.js:138:11)
      at process._tickCallback (internal/process/next_tick.js:180:9)

supertest@^3.0.0

A test fails with an undefined body when recent versions of supertest are used. The changelog mentions a couple buffer related changes that could cause this. This may also need to be fixed inkoa-body-parsers.

  1) Body Parsing .request.buffer() should get the raw buffer body:
     Error: expected 'message=lol' response body, got undefined
      at error (node_modules/supertest/lib/test.js:299:13)
      at Test._assertBody (node_modules/supertest/lib/test.js:216:14)
      at Test._assertFunction (node_modules/supertest/lib/test.js:281:11)
      at Test.assert (node_modules/supertest/lib/test.js:171:18)
      at assert (node_modules/supertest/lib/test.js:131:12)
      at node_modules/supertest/lib/test.js:128:5
      at Test.Request.callback (node_modules/superagent/lib/node/index.js:679:14)
      at node_modules/superagent/lib/node/index.js:868:18
      at IncomingMessage.<anonymous> (node_modules/superagent/lib/node/parsers/image.js:8:7)
      at endReadableNT (_stream_readable.js:1059:12)
      at _combinedTickCallback (internal/process/next_tick.js:138:11)
      at process._tickCallback (internal/process/next_tick.js:180:9)

[doug-wade]

Thanks @nickmccurdy