Make miniz.c compile cleanly on MacOSX:
- mark unused stuff with (void)
- remove unused function
- make the end of tge block be } while (0)
Cleanup to make it more modular and to make it compile on MacOSX:
- make .c files compile separately to .o files and then mini_gzip
- remove TEST_PROG stuff and structure. Test prog. lands in a separate file.
- structure lands in .h file