Issue #1968: Clarify grabber mechanics for newly-mapped channels.
Merge pull request #325 from bconway/master

Issue #1968: Doc fix - Clarify grabber mechanics for newly-mapped channels.
Add a channelno url to play a channel by its user assigned number
Merge pull request #324 from BtbN/channelnumber_http

Add a channelno url to play a channel by its user assigned number
Merge remote-tracking branch 'upstream/master'