Merge pull request #3 from fred-wang/localization

Some changes to the French localization data.
Fix a problem with localiztion when substituted value is 0.  Make language menu choices be in the given language.  Allow better localization of Jax/Extensions in About box.  Only update langauge menu when a new language is actually loaded.  Shorten a number of French menu items to improve menu appearance.  Correct some problems with FontWarnings and v1.0-warning messages.  Move language menu to initial MathJax menu rather than a submenu.  Fix a problem with canceling selection of renderer not reseting the menu selection.
Fix a number of message ID's and message texts.  Add menuTitle to fr.js file.
Add localization/en directory (never actually used, but can serve as template for other translations until we have a program that manages the data files).
Translate the strings added by Davide ; Reword some TeX translations.