update version number and permissions
rename StreamProtocol to CMDProtocol, since it no longer handles streams
but commands.
add support for playback of single songs
add methods to support new song type
add extra field for server-bind-address
rename PositionsUpdater to MainLoop, since it is now the main thread of
the plugin
add command /sc play <song> [world <name>|global]
backup old database if incompatible version is found and create a new
one
use the new server-bind-address configuration field