Add translations support to runtime.js,
and programs/editor/Translator.js which is a reference
implementations of a translator.
The programs/editor/Translator code is used entirely in
localeditor.js/collabeditor.js and the editor itself, or webodf,
and need not know anything about the translation mechanism.

Translate all strings within the editor and all
user-facing strings in webodf core itself using
runtime.tr();