php test progress

more php tests
fix error due to mismatching function names

fix error due to mismatching function names of DatabaseRow and its
derived classes
Exposed course insertion & deletion to the front end.
Minor edits for consistency.
Further implemented user courses.
Fixed the course selection bug.
Corrected minor errors.
Added course_lists.php and course_units.php.
Added “update()” stub.
Added stubs for user-preferred languages.
Improved session security.
Reenabled annotations_add() and annotations_remove().
Minor edit.
Added entry owner to the returned JSON.
Minor edit.
Mock object in tests

Mock object in tests, replace some static functions in Session class
more tests

more tests.. more to come
APIUserTest::test_lists

Finish APIUserTest::test_lists
APIList tests

Added Unit tests for APIList
more on tests

more on tests