Fix crash when parsing fen string with enpassant target
set NONE_PIECE as constant set to 0
Simplifying en passant moves generation
Simplifying macros definitions
Add more compilation options
make DEBUG-GCOV=1 to have Gcov support
make USE-INLINING=1 to force inlining (in debug mode)
make CLANG=C99 to compile in C 99

By default, USE_INLINING is enabled and assertions deactivated