Sarina/fix underscore resource

@singingwolfboy @louyihua this is necessary for the transifex pull commands to work.


Yep, I'm working on fixing this right now. Turns out we do need both `underscore-studio.po` and `underscore.po`, though, since we have some underscore templates under the `common` directory (even though they're only used by Studio at the moment, I believe).