ERT-518: Included ert_test_context in the general libenkf library - and removed test library ert-test.
ERT-518: Added set_store() method to ert_test_context
ERT-518: Added method enkf_main_get_fs_ref() which increases refcount on fs before returning; mainly for Python use.
ERT-518: Added ert_test_context as Python class.
ERT-518: Added python testing of enkf_fs.