server: Convert blob commands to lopsub.

server: Convert blob commands to lopsub.

This converts all blob commands (ls, cat rm, mv) in one go to lopsub,
making the patch rather large.

The addblob commands are special in that we must pass not only the
blob name given at the command line to the callback but also the
blob data which was read from stdin. The command handler does not
serialize the parse result like most other commands do, but constructs
a query object containing name and data for the callback. Therefore
the command handler does not call send_lls_callback_request() but
send_callback_request(). We continue to follow this scheme.

blob.c contains a few macros which expand to a set of functions,
one for each type of bloc (mood, playlist, image, lyrics). These
macros have to be adjusted to take another argument because we need
the prefixes (e.g., lyr for lyrics) in both upper and lower case and
there is no preprocessor toupper().