colorize more Printf functions

address the review
Merge pull request #844 from vasily-kirichenko/fix-printf-colorizing

Fix printf colorizing
add colorization profiling

change the way unused declarations are found
revert find unused declarations algorithm

SyntaxConstructClassifier returns file-based colorization first, then project-based
extract finding unused declaration logic out from GetAllUsesOfAllSymbolsInFile to GetUnusedDeclarations
SyntaxConstructClassifier keep Unused spans alive until new ones are ready in order to prevent blinking unused symbols/opens
fix a test
remove commented code