Port to Windows and MacOS

I have made several changes to make dhvani-tts build and run on the two main line operating systems.

For Mac, it is straight forward, but for windows, I had to create a separate Makefile.win in src and build using that. I could not get the autogen.sh work on cygwin/Windows combo. The Makefile.win is without the soundtouch though.

Overall, I found that it now works on the two OSs.