use SDL2 as ifdef symbol because we're not really sdl1.3 compatible, change the compatibility layer, drop unused code, add some documentation
*** 20020517: 1.0.2 ***
Playback bugfix to floor1; mode mistakenly used for sizing instead
of blockflag
*** 20020515: 1.0.1 ***
Added complete API documentation to source tarball. No code
changes.
*** 20020412: 1.0.1 ***
Fixed a clipping bug that affected ARM processors; negative
overflows were being properly clipped, but then clobbered to
positive by the positive overflow chec (asm_arm.h:CLIP_TO_15)
*** 20020403: 1.0.0 ***
Initial version