Update pot

Separate `test_wrappings`--a distributed server command for compiling dummy strings locally--and `update_po(t)`--a central server command for compiling current distributed server translations into `po` files.

Also added the following:
* Now avoid duplicates by separating translations by filename: `kalite.po` contains translations from compiling `py` and `html` (template) files; `kalitejs.po` contains translations from `js` files.
* By specifying the `--upload` option to `update_pot`, `pot` files with the latest necessary translations will be uploaded to crowdin.  Easy! :dancer: 
* Some other crap I'm forgetting now.

@dylanjbarth if you have the stomach to review, this'll bring back the good ol' days :)  Just have a looksie for the overall structure and anything you find interesting.