Improve error parser perf

This patch adds:
- a few improvements in the parsers (put the regexp compilation outside of the classes, reduced the num of iterations the error parser is run, use of substring search where appliable)
- support for cython in the log parsers moduels. I basically renamed them from .py to .pyx and run pyximport.install() before calling them where needed. There is probably room for further improvements because I didn't put any cython-specific code in those modules. We may want to do it one day