Rename CallableDescriptorCollectors.java to CallableDescriptorCollectors.kt
Rewrote CallableDescriptorCollectors to Kotlin
Rename: NO_RECEIVER_ADMITTED -> NO_RECEIVER_ALLOWED
Slightly reduce number of candidates in task prioritizer
  return only extensions (functions) when we expecting extensions (not all functions);
  for properties it's not that easy: they may have extension function types, and we want to avoid early computing of deferred types
  rename: getNonMembersByName -> getExtensionsByName

Report NO_RECEIVER_ALLOWED for '42.(f)()' where f: () -> Unit in TracingStrategyForInvoke
(we don't store candidates for such 'invoke' functions any more)
KT-5854 Incorrect 'Nested class should be qualified'
 #KT-5854 Fixed
KT-5455 Need warning about redundant type cast
 #KT-5455 Fixed
Small refactoring in CandidateResolver
KT-5971 Missing error when fun argument is safe call
 #KT-5971 Fixed
KT-6026 Exception on instantiating a nested class in an anonymous object
 #KT-6026 Fixed
Rename: casted -> cast
Refactoring: inlined 'collectSmartCastReceiverValues'
Optimization to not optimize imports on completion of class name if we do not insert any import
Optimized imports. Fixed build.
Fixed NPE
Renamed ReferenceSearcherImpl to IdeaReferenceSearcher
Repackaging
Minor
Big refactoring in j2k converter to support java&kotlin code updating to reflect changes in declarations produced by conversion (work in progress but all tests pass)
J2K: checked that field name change is correctly handled for usages in other converted classes as well
J2K: fixed conversion of base class constructor arguments