Add feature: go to #region in given Request

Also returns the locations of #endregion directives
Merge branch 'origin-feature-goto-region' into feature-goto-region

Conflicts:
	OmniSharp/GotoRegion/GetDirectivesASTVisitor.cs
	OmniSharp/GotoRegion/GotoRegionModule.cs
Properly rename GetDirectivesASTVisitor -> GetDirectivesAstVisitor
Merge remote-tracking branch 'refs/remotes/github/feature-goto-region' into feature-goto-region