First work on jQuery language extension

Need to find a good documentation way.
Of course methods need implementation!
Work on languages.js
Merge branch 'master' into guimier-messages
[languages.js] Fixed messages usage

Still need to build language change.
[ajax.js] Fixed boolean values to match PHP implementation

Also fixed syntax in languages.js
[languages.js] Added language change
[languages.js] Messages lists are objects, not arrays

Was querying the server for each language change, which is not needed.
[doc-js] Fixed syntax; improved documentation
Merge branch 'guimier-messages' of https://github.com/Guimier/zzchat