Fixed #22403  i18n js - AMD support

This is a patch for #22403

I have been having problems integrating the javascript i18n support with a complex javascript front-end. It would be tremendously useful for the global 'django' object - that is exported in 'django/views/i18n.py' - to also be exported as an AMD module. 

The AMD module supports is 100% optional. The 'django' javascript object is still exported as a global. 

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I also fixed some small linting errors. In javascript it is better to use strict comparison with [triple equals](http://www.jshint.com/docs/options/#eqeqeq).

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Suggestion for further modification:

I think that ideally, django would create a json object for each language catalogue and then the javascript client would make an xhr request for that file. Then there would no longer be a need to dynamically create javascript. In that case, that javascript could be bundled with the rest of the applications javascript - eliminating potential load time issues.