update sdl apis to use the new rendering functions

- Take into account hlint suggestions - Fix almost all warnings

Don't accept EM message when the game isn't started

fix issue #185 :| also fix compilation & universal binary stuff for hwlib under macosx

I need this export in order to not have the wrapper.c fail to find Game() on linux From this point on compilation and usage of library should work on linux, at least does for me :P

fix engine library compilation on linux/amd64

remove redundant note