Fix CppUTestExt installation to include MockSupport.h and MockExpectedFunctionCall.h

Signed-off-by: Matt Keeler <mk@npulsetech.com>
Added protection against being included from a C file
Added better support for Visual C++ features
Commented out the warnings to see if they're needed
Fixed a failing test
Fixed how MSC_VER is checked to not error on gcc and clang
Regenerated Makefile.in
Merge pull request #262 from Andne/vcfixup

Visual C++ Fixup/Improvements
Merge pull request #260 from mkeeler/master

Add missing headers to cmake install