PathDiagnostics:

- PathDiagnosticControlFlowPiece now consists of a "start" and "end" location
  to indicating the branch location and where the branch goes.

BugReporter:
- Updated BugReporter to construct PathDiagnosticControlFlowPiece objects with
  "end" locations.

PlistDiagnostics:
- Plists now contain the bug "type" (not just bug "category")
- Plists now encode control-flow pieces differently than events; now the
  "start" and "end" locations are recorded

llvm-svn: 66818