MRuby: Update module_rpg.c to newest bytecode format
Add placeholder application icon
Allow inserting GL string markers (GREMEDY_string_marker)
Rename src/debuglogger -> src/gl-debug
debugwriter.h: Use unbuffered cerr instead of clog
README: Add prebuilt windows binaries link
Tilemap(VX): Factor out common code into tilemap-common.h

Renamed flashmap.h to tilemap-common.h as it already contained
shared functions.
Don't use relative paths when #including xxd output