The bool data type was redefined to BOOL (4 bytes on windows).
Removed the #define and fixed some of the warnings that were uncovered
by this.
Note that the fix also disables 2 warnings :
4800 : 'type' : forcing value to bool 'true' or 'false' (performance warning)
4805: 'operation' : unsafe mix of type 'type' and type 'type' in operation

These warnings will be handled in a separate bug, as they are performance related or bogus.

Fixed to int the return type of functions that return more than 
2 distinct values.