Rename some functions in capabilities.h
Rename some functions in capabilities.h

This fixes compatibility with commit 508c45bc of libmpdclient

The following functions were renamed:
send_commands       -> send_allowed_commands
send_notcommands    -> send_disallowed_commands
send_urlhandlers    -> send_list_url_schemes
send_tagtypes       -> send_list_tag_types

alip/luampdclient,alip/luampdclient