0.27 ASM Optimizations

This is a minor incremental release with a number of bugfixes and a large amount of code moved from C to asm, resulting in a smaller and slightly faster binary.

(Remember, if you get a "Game mode indeterminate" error, that just means you need a doom wad in the directory)

Running directory will require a doom wad, dstrings.txt, DOOMDATA.bin, then the DOOM.EXE and DOOMCODE.BIN pair from a particular build type.

Some example configurations for CONFIG.SYS included. The main memory requirements are:

D000 Page Frame for Music (64k)
E000 UMBs (64k)
256-640k as a pageable conventional EMS region

I've removed the D000 build and chipset builds from this release. I consider this a minor release and want to move on and focus on the hopefully upcoming alpha release.