fixed PY-11595 Unable to move lines within Python doc strings
fixed PY-11594 New Project: selected interpreter is not set as project interpreter when attaching project to already opened one
Call static methods via classes where they are actually defined
Removed stdlib type cache unused after the switch to python-skeletons
Removed unused PyBuiltinCache.isValid()
Rearranged fields and constructors
Fixed PIEAE in referencing obsolete cached PSI elements for built-in 'str | unicode' type

There was no significant performance boost, so the cache has been simply removed.
Merge branch '133' of git.labs.intellij.net:idea/community into 133
Added ellipses for skeleton processing progress messages
Switched from showing balloons to logging errors for serious skeleton generation exceptions
Moved skeleton generation progress on adding a Python interpreter to background
Nullity annotations for overridden methods
Removed unused PythonSdkType.switchPathToInterpreter()
Call a static method via its defining class, not its subclass
Don't report unresolved references and unused imports if the project interpreter is not selected (PY-11589)
Return unknown return type for generator functions if the built-in generator type is not found
Don't report unresolved references and unused imports during skeletons generation
Don't show python-skeletons path in the Python interpreter paths tab (PY-11218)
Don't add python-skeletons to Python paths during skeletons generation
Switched to synchronized count of running Python skeleton generators