#KT-2240 fixed

#KT-2236 Fixed

 #KT-2206 fixed

 #KT-2193 fixed

Revert commit because two commits fixing separate bugs were accidentally stuck together. Will recommit bugfixes separately.

Revert "KT-2193 Nullability information lost for functions inherited from traits".

This reverts commit d60818fd.

remove attempt to optimize using 'if' statement as the last one in a loop which created far more problems that it fixed

#KT-1978 Fixed

 #KT-2193 fixed

Added storing modality for trait members in @JetMethod annotations.

 #KT-2228 Fixed

Replaced JetMethodAnnotationWriter.writeFlags(BitSet) method with method taking indices of bits which should be set.

Added JetMethod.flags() to replace kind(), with adding extra functionality (modality and visibility marking).

Made methods in AlternativeSignatureParsing throwing AlternativeSignatureMismatchException and added proper handling of them.

#KT-1932 Fixed

I was wrong about not redirecting getClassifier() to parent

Writable scopes do not redirect getClassifier() to parent

 #KT-2234 fixed

KT-2103 Compiler requires return statement after loop which never exits
 #KT-2166 Fixed
 #KT-2103 Fixed

while reversed order is needed
not only reachable from sink instruction

 #KT-2226 fixed