* Added a 'CUTS.SHA1_HASH' field to the database.
* Incremented the database version to 261.
* Added a 'Sha1' column to the Cut List in 'rdlibrary/audio_cart.cpp'.
* Added 'RDCut::sha1Hash()' and 'RDCut::setSha1Hash()' methods in
'lib/rdcut.cpp' and 'lib/rdcut.h'.
* Added a '--rehash=' directive to rddbcheck(8).
* Added a 'Rehash' Web API call.
* Added an 'RDRehash' class in 'lib/rdrehash.cpp' and 'lib/rdrehash.h'.