Cleaning up FactoryFDAFeatures.getFDAFeature(filename). There is no
need, I think, to itererate over all .sparql files, as filename is given
in input parameter. Change was necessary since a large number of sparql
files (~50 file) caused too many open file handles.

Also adding JsonReader.setLenient(true) to accept my JSON files.
Adding support for simple authentication against SPARQL endpoint.
Merge branch 'master' of https://github.com/mgskjaeveland/lod4wfs