- create new IProblemLocationCore class in jdt.core.manipulation
  based on IProblemLocation
- create new ProblemLocationCore class in jdt.core.manipulation
  that implements IProblemLocation
- have ProblemLocation in jdt.ui extend ProblemLocationCore and
  as well implement IProblemLocation

Change-Id: Id1ce30ff5bf689d9be3c767a8bf062df294d19bf
Signed-off-by: Jeff Johnston <jjohnstn@redhat.com>