Add whisper.cpp (server) support to llamafile

[cjpais]

This PR adds whisper.cpp support to llamafile. This addresses #17 in part. Only the server binary has been ported in this PR.

Most of the work to support this was initially done on my fork of llamafile: whisperfile. This PR ports the code over, and structures it similarly to stable-diffusion.cpp support

The whisper.cpp code was taken from commit: 6739eb8