IDEA-129339: show tracked branches in general "remote/..." groups

(cherry picked from commit 209ebc2)
IDEA-16393 diff: prefer diff walker action in case of keymap conflict

allow to use same shortcut, as Next/Previous method
(cherry picked from commit 32e1486)
IDEA-123196 diff: do not step over applied changes

This will also affect SynchronizedScrolling, but it shouldn't be crucial
(cherry picked from commit ff0c9ff)
IDEA-123196 diff: do not step over applied changes

paint applied changes on divider
(cherry picked from commit d288dfc)
IDEA-115799 diff: fix changes painting over scrollbar in 3-way panel

do not eat 100% of CPU due to recursive calls of repaint()
(it was not lead to deadlock, so was not fixed all this time).
(cherry picked from commit 0046ae2)
diff: better painting of changes over scrollbar in three-way diff panel

* we don't need to care about thumb size, as now we are painting between background and thumb, not over them
* we don't need to explicitly paint changes on paint(), as they will be painted by scrollbar
(cherry picked from commit 7d9a7a7)
diff: draw applied changes on scrollbar
(cherry picked from commit fc38756)