Remove compiled locale json/js

Remove the built js/json from the tree so we can do it at deploy so locale commits result in live localisations.

Also if compilation bails due to something bad in the PO the tests will bail.

~~r? @clouserw~~

Re: conversation in the hangout - we're good to go on this (extraction + merging is still manual) but the compilation at build time would be equivalent to what django does. 

~~TODO: fix conflicts~~