GitLab

* Converted CTagsRunner into a function

* Removed useless tasks from ctags_runner test

* Simplified ctags_runner test

* Removed some ctags related fields from builder context

The last piece in RunCTags:

 	parser := &ctags.CTagsParser{}
 	parser.Parse(ctagsStdout, sketch.MainFile)
 	parser.FixCLinkageTagsDeclarations()

 	prototypes, line := parser.GeneratePrototypes()
 	if line != -1 {
 		prototypesLineWhereToInsert = line
 	}

has been moved at the beginning of PrototypesAdder.
RunCTags now returns the output of ctags instead of `prototypes` and `line`.
This also allows to remove the context variables that keeps those
information.

* Simplified RunCTags / factored test subroutine

* Removed DebugPreprocessor from builder ctx

* Added executils.RunAndCaptureOutput

* Moved RunCTags out of legacy package