implemented MVP for https://github.com/globaleaks/GlobaLeaks/issues/950

@hellais i've implemented the MVP for https://github.com/globaleaks/GlobaLeaks/issues/950.

 it's complete and ready to be integrated apart that due to techincal reasons i've not currently found a way to make the loader (and the detection) available in the non-build version of the glclient. can you please take a look? may be you have an easy solution.