Modify tester.py to accept __name__ as the input for identification of working directory as per a suggestion from Mark S.  Modify image and convolve to support this new API.  Also, change the installation files for image and convolve such that image.tests and convolve.tests are installed as packages instead of data files.
Modify tester.py to accept __name__ as the input for identification of working directory as per a suggestion from Mark S.  Modify image and convolve to support this new API.  Also, change the installation files for image and convolve such that image.tests and convolve.tests are installed as packages instead of data files.

git-svn-id: e4aa3cfa51ba591d1cd1dbbaf7e4a2c2b5d7a7ff@8661 fe389314-cf27-0410-b35b-8c050e845b92

spacetelescope/stsci.tools