Initial implementation of printf highlighting

Only those print functions that have the formatting string in the first position are enabled. Missing are: bprintf, fprintf, fprintfn, kbprintf, kfprintf, kprintf, ksprintf
Merge branch 'master' into printf

Conflicts:
	src/FSharpVSPowerTools.Core/SourceCodeClassifier.fs
	src/FSharpVSPowerTools.Logic/SyntaxConstructClassifier.fs
	src/FSharpVSPowerTools/SyntaxConstructClassifierProvider.cs
	tests/FSharpVSPowerTools.Core.Tests/SourceCodeClassifierTests.fs
Merge branch 'master' into printf

Conflicts:
	src/FSharpVSPowerTools/SyntaxConstructClassifierProvider.cs
Merge remote-tracking branch 'fsprojects/master' into printf

Conflicts:
	src/FSharpVSPowerTools.Core/SourceCodeClassifier.fs
	src/FSharpVSPowerTools.Logic/SyntaxConstructClassifier.fs
	src/FSharpVSPowerTools/SyntaxConstructClassifierProvider.cs
	tests/FSharpVSPowerTools.Core.Tests/Coloring.fs
	tests/FSharpVSPowerTools.Core.Tests/SourceCodeClassifierTests.fs
Merge remote-tracking branch 'fsprojects/master'