[bug 902108] Add dennis v0.3.7 to vendor/

This updates polib and adds dennis to vendor/. Now we can do things
like:

    ./manage.py lint
    ./manage.py translate

Also, this nixes poxx.py and localelinter.py which aren't needed
anymore.
[bug 902108] Add compile-linted-mo.sh script
[bug 902108] Fix deploy script to run compile-linted-mo.sh
Fix path to compile-linted-mo.sh in deploy script
Back out the compile-linted-mo.sh change

The update_locales step went from like 6 seconds to 528 seconds. That's
too slow. I'm backing it out for now to look into it.