[mythtv] I have merged MythUI settings into master

[Peter Bennett]

I have merged the MythUI settings (devel/mythui/settings) into master. 
Status of outstanding settings bugs are in #13046 
(https://code.mythtv.org/trac/ticket/13046). The outstanding bugs are 
minor in nature and I will be working on them in master. The branch 
devel/mythui/settings will no longer be used for this.

Let me know if there are any issues/problems with this. Also feel free 
to add comments or problems to that ticket.

Peter