Javascript code review script - for use with Travis CI

Here is a proposal for code reviewing the javascript GEOR_Lang/ files, following the conventions defined in the #4297 ticket (http://forge.applis-bretagne.fr/issues/4297).

This PR propose to verify some of these conventions using a node.js script. The good point is that the test may be automatically launched for each **push** in the geOrchestra repository, using Travis CI.

See for example: https://travis-ci.org/severo/georchestra/builds/6658793.
* the test failed, indicating that errors have been detected (coding conventions not respected)
* the log indicates where is the error (file + line number) and what is wrong (which rule is broken).
As for now, there are 243 errors (243 lines where the conventions were not respected).

I used node.js for its module called esprima (http://esprima.org/demo/parse.html) dedicated to javascript code parsing.

If this PR is accepted, I will configure Travis CI in order to send a mail to the repository owner when the test fails.

Note that this PR just creates a tool for detecting errors. We still need to correct them.