Added win32 compatibility

[mp81ss]

1. Bypass the BINDIR variable and just search executables in the same directory of uno.exe (no paths, just the base name, the 3 exe files must be in the same folder
2. Added "del /Q" option (rm -f was the only one present)

The only file changed is uno.c

With this changes, linux build remains untouched but gcc win32 compile/run correctly