concise outputs for python setup.py nosetests.
Overflow of month, hour, etc. raises ValueError
always raise ParseException. clears out the crud inside test_samples.py,
at the cost of emitting error messages whose vagueness approaches that
of $(CXX).
Test for strings with invalid escape sequences

There are two bugs here:
* \U makes Python think this is a Unicode code point
* Other escape sequences like \p should raise