Add TargetDirectoryManipulator Phase

This adds a new phase, TargetDirectoryManipulator, that enables
manipulation of the TargetDirectoryAnnotation using two annotations:

  - TargetDirectoryEnterAnnotation which changes the TargetDirectory
    to a subdirectory
  - TargetDirectoryExitAnnotation which enters the parent directory of
    the current TargetDirectory

This also adds a helper phase, TargetDirectoryExit, which will add a
TargetDirectoryExitAnnotation.

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>