Added Python 3.4 modules to the stdlib modules list
Fixed code insight for returning 'self' in base class methods (PY-10977, PY-11413)

If a method of a base class returns a value of this class, then it is
cast to a derived class this method has been invoked on. This cast is
considered safe, since it cannot result in false positives.
Python skeletons class members provider now can provide new overridden members

It is useful for overloading method signatures in subclasses.
Added 'inherited' parameter to PyClass.findProperty()
Extracted PyClassTypeImpl.findProperty()
Simplified always true condition
Nullity annotations
Return instance types for instance types of superclasses
Detect text or binary I/O in pathlib.Path.open()
Handle 'mode' as a keyword argument to open() as well
IDEA-118389 Forbid completion inside guard blocks; honor greediness
Merge branch 'python3.4'
WI-13685 PhpStorm doesn't save project name CR-PS-181
(cherry picked from commit ed41c77)