Fypp support

[aradi]

Offers improved user experience for projects which use Fypp as pre-processor:

• Automatic test registration
• CHECK() macro calling the check() routine with automatic file name and line nr. information
• ASSERT() macro calling CHECK() and returning from the test, if the check failed.

The approach is currently only tested with CMake due to the lack of proper support for preprocessing in the other build systems.

Todo

• Make final decision on macro names and arguments.
• Install fypp include file when project is installed
• Enable CMake projects using Fortuno to deduce the location of the include file's folder somehow (via a fake target)