fix some compiler warnings.
update the emscripten port.
reduce bss a little (as emscripten blatently can't cope with it)
support for '_wateralpha'. also support for cvar_foo too.
demo_jump works in nq demos.
git-svn-id: https://svn.code.sf.net/p/fteqw/code/trunk@4732 fc73d0e0-1445-4013-8a0c-d673dee63da5