CMake Changes - INT32_MAX Fix. Debug/Release Output Folders

 - Added __STDC_LIMIT_MACROS definition to CMake to resolve the INT32_MAX error (as mentioned in issue #398 )
 - Altered CMake files so that -CMAKE_BUILD_TYPE=Debug will output built files to Polycode/Debug rather than Polycode/Release. -CMAKE_BUILD_TYPE=Release will still continue to output to Polycode/Release.
 - The Makefile in Polycode/IDE/Build/Linux has been edited to reflect these changes so that it will find debug files (when ran as `make debug`) in the Polycode/Debug folder rather than the Polycode/Release folder.