fixed NPE while opening first task in new study project
EDU-232 Cancel task window text editing actually doesn't work
EDU-234 Generated python file becomes visible after .answer file was deleted
Update test of JSON's structure view (broken after IDEA-131495)
open first task: refresh directory, stop with project dispose
Merge remote-tracking branch 'origin/master'
[git] make some git push classes & methods public by request of gerrit plugin author
[push] IDEA-130622 Temporary fix for "confusing selection" problem: select all repositories with commits.
[vcs] cleanup: String.format() to ease reading
[vcs] Don't notify about "less interesting" unregistered roots

IDEA-87769 roots not under project dir;
IDEA-98781 roots under ignored directories.

But still show them in the Settings.
[vcs] IDEA-131859 Fix grammar
IDEA-130848 Push dialog initial selection & enabling policy

* remember unselected roots and store in workspace.xml;
* don't select and don't load excludedRoots;
* always enable push button for mercurial;
* load all repos for git exclude remembered;
* wait until all or one repo loaded according to sync branch settings;
* always allow push for git new branch;
* preselect git repos only from project view and ignore current editor 'selection'
IDEABKL-6086 Distraction Free mode
catch AbstractMethodError for old api clients
fixed EDU-233, switched to flat model in offset listener
load all roots for git and for sync hg
don't evaluate arrays on EDT when debugging remotely

(cherry picked from commit ed2a20feeec3dad31e25d5e027940cf85f2b065f)
remove code duplicate (use isUnderRemoteDebug directly)

(cherry picked from commit 43b8a662654406422ad01743841324736c5d7214)
Platform: extensible welcome wizard:
* themes page can be customized
* additionas UI setting supported
IDEA-128476 UI of Customize IDE wizard is broken after theme change