Initial work on supporting Microsoft Word files.

Add an extra file extract-doc.cpp based on extract.cpp. Pick which extract
function to use based on file extension.
Check whether .doc file is encrypted
Change extract to only return the encrypted verifier and hash

Previously it returned the whole FilePass record. This is needed because
.doc files don't use the FilePass record.
Complete extract_doc - read encryption data from 1Table
Delete blank lines (minor)
Implement decryption of MSWord documents

It remains to change the bit that says the document is encrypted.
Clear fibBase.fEncrypted
Tidy-up, removing spaces at end of lines and debugging print statements