[epg] drop unused variable from SetUpdatePending()
[epg] make CEpgContainer constructor private since it's a singleton
[epg] remove unused bDeleteFromDatabase parameter, it's always set
to true anyway and it's value is ignored when "store EPG in database"
is disabled
[pvr] drop "bSaveInDb" parameter from the MoveChannel methods, it's always
true anyway (and why would anyone *not* want to persist a move?)
[epg] drop "bForce" parameter from CreateChannelEpgs, it's always
been false
[pvr] remove pointless check for internal group, the method just returns
true if the group is not internal
[epg] make CreateChannelEpgs() return true only if the EPG was
created for all channels
[epg] don't reset the EPG channel pointer when the channel is deleted,
the EPG is deleted anyway