CodeCoverage:FileID/Document SequencePoint Attrs

Fixing [CodeContractClass/For] using SequencePoint fileid/url XML
attributes
CodeCoverage: Use new OpenCover attributes

Now is simpler/cleaner to find start/final SP
Remove obsolete methods & code
CodeCoverage: CCMethod FileID and SequencePoints

CodeCoverageMethod:
New method property .FileID
Filter Visited & Unvisited SP by Method.FileID
CodeCoverage: CCControl SequencePoint filter

CodeCoverageControl: Do not show SequencePoints from another file
CodeCoverage: Remove obsolete BranchPoint code
CodeCoverage: Null reference fix, remove Debug ...

CodeCoverageMethodElement:
Null reference thrown because Tests does not contain new attributes,
fixed.
Debug.Fail breaks Test, removed.
CodeCoverage: Test
CodeCoverage: Applied SD5 suggestions
CodeCoverage: Tests
Merge branch 'dd.NextOpenCover' of https://github.com/ddur/SharpDevelop into dd.NextOpenCover