This feature removes the dependency on malloc/free for constrained
  embedded systems without a heap. It uses a static heap inside
  Unity Fixture. Setting UNITY_INTERNAL_HEAP_SIZE_BYTES sizes the heap.
 Add tests for new option, add targets to makefile for running tests.
 UNITY_FIXTURE_MALLOC for Fixture use only, remove from unity_output_Spy.c.

 For redefinition of UNITY_FIXTURE_MALLOC/...FREE use both or replace both.
 Clean up whitespace, remaining void*, and comment.

Fixes #116: Allow overrides of the Unity Fixture's memory functions. This enables custom heap implementations to be used with the Unity Fixture.

Fixes #3: unity_fixture tests don't build. unity.c and unity_fixture_malloc_overrides.h neglected to include <stddef.h> even though the reference 'size_t' and 'NULL'.

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.

git-svn-id: http://unity.svn.sourceforge.net/svnroot/unity/trunk@106 e7d17a6e-8845-0410-bbbc-c8efb4fdad7e