Changes since 1.4:
 . Document sessions in the genomix HTTP protocol
 . Bump to 1.5 for the newly added requests
 . Implement the '/version' request, returning genomixd version
 . Implement the "/usage/<component>" request, returning the supported options
 . Catch up with changes in client interafce 20140611 (genom3-2.99.24)
 . Fix a few issues regarding incorrect list vs. string usage