static: Add a js languages file

This file will be autogenerated by make linguas once some fixes are
upstreamed to TTK.
static, templates: Add a global language picker
profile: Remove ui_lang from the profile
Don’t try to update non-existent summary

Fixes the misleading error:

  TypeError: view() got an unexpected keyword argument 'dir_path'

Which was the result of making an AJAX request with empty URL that gets
interpreted as index page view() which is not prepared for AJAX requests
(and shouldn’t).
Remove non-existent logging bit that sneaked in

Those are related to logging changes in Evernote’s fork that we did not
pick, I failed to remove those while merging which broke submitting
translation! If we decided to pick the new logging code, this commit
should be reverted.
travis: compile all Python files

Catch syntax errors early, especially in files that we might not test
during installation.