Fix docs.

- fixed ANSI (C89) issues, including #418

Add TEST_MESSAGE for outputting messages without aborting a test and _MESSAGE variant to TEST_PASS collection.

- Tweak a couple style problems with Ruby scripts.

Added include of 'stddef.h' to 'unity_internals.h' if 'UNITY_EXCLUDE_STDDEF_H' is not defined. This adds compiler independent support for the 'NULL' macro.

Fixed grammar errors and some sentences to make it easier to understand

Added notes, why _MESSAGE assertions do not support printf style formatting and how users can work around this limitation (see #331)

Adds support for :mock_suffix when generating mock setup and teardown
functions. Also documents both prefix and suffix in the helper script
guide.

Added more detail on test naming.

Help error detection by adding specific colors for test results. This
behavior is activated only when unity if compiled with UNITY_COLOR flag.

Add newlines after headings for best practice, trim trailing spaces & convert sneaky incorrectly coded chars

blank newline after headins is apparently best practice according to http://stackoverflow.com/q/42953462/1292918

Add GFM version of getting started guide PDF

Add GFM version of configuration guide PDF

Add GFM version of helper scripts guide PDF

Add GFM version of coding standard PDF

Add GFM version of assertions reference PDF

Change markdown used to italicise line. Switched to use asterisk markdown instead

Turn UNITY_OUTPUT_FLUSH off by default. Added a quick-define for the most common case: UNITY_USE_FLUSH_STDOUT. Clarified documentation. Fixes issue #269

The class gives back to the community: better documentation produced for the class and now part of the open source project

- tweak docs

We're going to use the C99 isinf() and isnan() macros wherever possible now. If your compiler doesn't support this, define UNITY_EXCLUDE_MATH_H and it will go back to the old method