Localeapp roundtrip + fixes

This includes an overdue synchronization of plugin locales. To make
translation easier for non-developers, we keep the strings at localeapp,
which puts everything in one file. All plugins enabled by default are
therefore included in Foodsoft's locales.

plugins/messages/app/views/message_threads/index.html.haml

@@ -2,7 +2,7 @@
 
 = render 'messages/actionbar', active: 'message_threads'
 
-= render 'groupmessage_threads', group: nil, name: t('.other'), id: 0
+= render 'groupmessage_threads', group: nil, name: t('.general'), id: 0
 
 - for group in @groups
   = render 'groupmessage_threads', group: group, name: group.name, id: group.id

plugins/messages/app/views/message_threads/show.haml

@@ -1,5 +1,5 @@
 - if @group.nil?
-  - title t '.other'
+  - title t '.general'
 - else
   - title @group.name