graying unused declarations
SourceCodeClassifier peeks meaningful categories, then Other, then Unused if there are many for one symbol

fix the order in which SourceCodeClassifier peeks categories

fix compilation
Merge remote-tracking branch 'fsprojects/master' into graying-out-unused-declarations

Conflicts:
	src/FSharpVSPowerTools.Logic/RenameCommandFilter.fs
Merge remote-tracking branch 'fsprojects/master' into graying-out-unused-declarations

Conflicts:
	src/FSharpVSPowerTools.Logic/SyntaxConstructClassifier.fs
	tests/FSharpVSPowerTools.Core.Tests/SourceCodeClassifierTests.fs
Merge remote-tracking branch 'fsprojects/master' into graying-out-unused-declarations

Conflicts:
	src/FSharpVSPowerTools.Logic/VSLanguageService.fs
refactor according to code review
Merge pull request #500 from vasily-kirichenko/graying-out-unused-declarations

Graying out unused declarations