Add support for win32

win32/.cvsignore

win32/README.win32

win32/all.dsp

win32/all.dsw

win32/all.opt

win32/ao.def

win32/ao.dep

win32/ao.dsp

win32/ao.dsw

win32/ao.mak

win32/build_all.bat

win32/clean_all.bat

win32/clean_dist.bat

win32/example.dep

win32/example.dsp

win32/example.mak

win32/exmaple.dep

win32/exmaple.mak

win32/include/dirent.h

win32/include/dlfcn.h