escaped symbols are colorized in the simplest case
add more tests
Merge remote-tracking branch 'fsprojects/master' into colorize-escaped-chars

Conflicts:
	src/FSharpVSPowerTools.Core/SourceCodeClassifier.fs
	src/FSharpVSPowerTools.Core/UntypedAstUtils.fs
	tests/FSharpVSPowerTools.Core.Tests/SourceCodeClassifierTests.fs
SourceCodeClassifier highlights escaped symbols
Merge remote-tracking branch 'fsprojects/master' into colorize-escaped-chars

Conflicts:
	tests/FSharpVSPowerTools.Core.Tests/SourceCodeClassifierTests.fs
tune escaping symbols color
Merge remote-tracking branch 'fsprojects/master' into colorize-escaped-chars

Conflicts:
	tests/FSharpVSPowerTools.Core.Tests/SourceCodeClassifierTests.fs
Merge remote-tracking branch 'fsprojects/master' into colorize-escaped-chars
address the code review
address the code review
Merge pull request #786 from vasily-kirichenko/colorize-escaped-chars

Colorize escaped chars