Fixing warnings in CryptoMiniSat

Thanks to Stephen McCamant for spotting these
Re-licensing CryptoMiniSat to MIT licence in the headers as well

It has been documented that I have re-licensed this version of
CryptoMiniSat for an MIT license. It's now indicated in the header
files, too
Re-licensing CryptoMiniSat (cont.) to MIT licence in the headers as well

It has been documented that I have re-licensed this version of
CryptoMiniSat for an MIT license. It's now indicated in the header
files, too
added all contributor names
i
Made some relevant changes to headers to AST and Printer files. Added back David Dill's name which was inadvertently removed.