Added image optimizer.
Renamed grunt task name to 'images'.
Covered more images with the grunt task and made JSHint accept the grunt file.
Optimised images.
Changelog entry.
Merge branch 't/12338'
Fixed calls onNavigationKey method in some situations.
Tests: Pretend the editable's events are bubbling.
Changelog entry.
Merge branch 't/12324'
Decreased listeners priorities in undo manager.
Changelog entry.
Merge branch 't/12332'
JSHint and JSCS fixes in the main dir's files.
JSHint and JSCS fixes.
JSHint and JSCS fixes in tests.
Tests: Fixed HTML comparison on IE8.
Tests: Fixed unstable HTML comparisons.
Tests: commented out two cases because of #12474.
JSHint and JSCS in walker tests.