Need better error reporting in

[schwehr]

The error report should report which files and line numbers caused the error(s).

e.g. from where in typeexamples.json typeexamples.nmea

FAIL: testTypeExamples (test.compatibility.gpsd_test.StreamingTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/local/google/home/schwehr/src/libais-2/test/compatibility/gpsd_test.py", line 141, in testTypeExamples
    self.validate_file("../data/typeexamples")
  File "/usr/local/google/home/schwehr/src/libais-2/test/compatibility/gpsd_test.py", line 129, in validate_file
    self.assertFalse(diff['changed'])
AssertionError: {u'sub_areas': ([{u'sub_area_type': 0, u'sub_area_type_str': u'circle', u'precision': 4, u'radius': 9260, u'y': 42.082950592041016, u'x': -69.86498260498047}], [{u'sub_area_type': 0L, u'sub_area_type_str': u'circle', u'precision': 4L, u'radius': 9260L, u'y': 42.08295, u'x': -69.86498333333333}])} is not false