Updated clang and gcc targets. Fixed spelling of LIMITS, which breaks the
  gcc_auto_sizeof.yml build.
 Commented -Wunreachable-code, Unity won't build on OSX clang with it,
  error in unity.c:769 & 932: 'default: break;' case.

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

Primarily -
* Added "static" to static functions.
* Added proper signature with "void" to functions without arguments.
* Marked unused arguments with "(void)".
* Removed entirely unused static functions.
* Added "const" to preserve const-correctness.
* Added function prototypes for external functions.

rearranged project to centralize all self-test stuff under test directory. only pull in includes when required.