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