This was already done in Python3, but having it wrong leads to
incorrect debug output, so it seems worth fixing in 2.7 as well.

Patch by Victor Terrón.

Ezio.

Ezio.

#17526: fix an IndexError raised while passing code without filename to inspect.findsource().  Initial patch by Tyler Doyle.

#8906: document failureException, longMessage, and maxDiff in the class docstring.  Patch by Boris Feld.

Closes #4159: add LaTeX tabular column specifications to tables that otherwise are cut off or have overlapping text.