Stop try to lex for matching braces in interpolation if the token_re matches an empty string. This fixes the infinite loop triggered by the test suite as a result of the change to Python 2.7 describe in http://bugs.python.org/issue16152 and reported in http://genshi.edgewall.org/ticket/540.

#!/bin/sh
#
# Script to run 2to3 on files not covered by setup.py
#
export PYTHONIOENCODING=utf8

# General 2to3 run
2to3 -w --no-diffs examples/