Change to MinGW build script
Made all function declarations explicit in core.y

This resolved numerous compiler warnings, but one still needs to be
figured out. Added *.err exclusion to .gitignore.
Set cl warning level to W2
Trim some padding in banner
Add logo, add *.exe to .gitignore
Add Open Watcom C32 1.9 build script, plus

- minor changes to formatting;
- main returns value (always 0 for now);
- explicit prototype for yylex();
- change unsigned char -> int for conditional[] and conditional_level;
- changed type from unsigned int to size_t for variable compared to
return of strlen() in write_text()
Remove -O2 optimization from build scripts

Will return once there is a proper test unit suite
Add GNU header to main C file

also some code reformatting to make it easier to read
Update README.md file with new project work items
Refactoring

- all WAV writing code moved to a separate unit (wav.c/wav.h);
- changed VERSION macro name to ASMSX_VERSION to avoid clash with any
other VERSION macros;
- replaced hard-coded magic value 0x100 with ASMSX_MAX_PATH macro, kept
the value as is at 0x100;
- moved shared constants and function prototypes from core.y to asmsx.h
file;
- added some explicit type casting to core.y to suppress compiler
warnings;
- updated build scripts and makefiles to support changes above.
Merge pull request #2 from oboroc/master

Catch up on changes from my fork