Addresses #1976 by implementing click->hold to rename for the project tree.
Tweaked the timing threshhold based on some additional testing.

Also cleared up the comment.
Changed behavior based on @njx feedback.
Moved to mouseup event.
Fixed issue with double-clicking not working.
Fixed issue where you couldn't double click on a selected item to add it to the working set.
Fixed issues from review.
Final nits fixed. Good call @njx!
Merge pull request #7955 from adobe/ryanstewart/issue1976

Addresses #1976 by implementing click->hold to rename for the project tr...