Show recent additions in Special:Translate if no group chosen

Change-Id: I115c24f2c2733c835516a500f51474a5c39bf81f
Some code refactoring to reduce ugliness

* Pagers are now handled by message tables
* Need to pass more data from Special:Translate to message tables
  via TranslateTask, dropped TaskOptions
* Optional "works" now in tux, though not with ajax loader

Change-Id: I5a168a23eb1e244fc6c3143d68b6f0df933e705f
Merge "Some code refactoring to reduce ugliness"
Merge "Show recent additions in Special:Translate if no group chosen"