Maruku uses greedy Regexps in a number of places, which,
in unfavourable circumstances, can lead to exponential
slowdowns (an apparent hang).
We worked around one such bug in Revision 355. Recently,
Toby Bartels found another (in Table Header parsing).
The "real" solution seems to be to make sure the Regexps
are not greedy. (Thanks to Sam Ruby for spotting the problem!)
Reverted the workaround in Revision 355, fixed Toby's
bug, and several other similar Regexps.
7403ea6a6b