Remove redundant "private tabs" feature.
|Status:||In Progress||Start date:||06/13/2015|
|Target version:||Orfox RC|
The "private tab" feature includes a completely separate tab bar from "regular" tabs, and separate menu choices to open tabs into either place. Since "regular" tabs in orfox should be no less private than "private" tabs, this can be unnecessarily confusing (i.e. not finding a tab you opened because it's in the other tab list).
Mention of "private" tabs also implies that refular ones aren't private, which (I hope) won't be true.
It would be a nice simplification of the UI to simply have one tab list, and only one kind of tab.