EA-54015 - assert: DocumentImpl.doRemoveDocumentListener
diff: LST - remove TODO

optimization is made by "fixRanges"
diff: LST - add defensive checks

The cause of out-of-range lines is under investigation
diff: cleanup
Visual improvements for banner in the Settings dialog
IDEA-127409 (correct findElementAt() implementation for .class files)
EDU-161 python file becomes visible after task file rename
one more attempt to make html parser follow attributes spec and make angular 2 happy