Add dedicated count extractor.
Add dedicated controls extractor.
Remove "kind" property from metadata callback.
Add composite metadata extractor.
Allow an array as argument for CompositeExtractor.
Make extractors inherit from MetadataExtractor.
Use metadata extractors in fragments client.
Merge TriplesIterator with TurtleFragmentParser.
Only merge metadata if necessary.
Merge branch 'feature-metadata-extractor'
Remove unused code for single-element fragments.
Make TranformIterator's source optional.

This is a breaking interface change.
Before, if you wanted to set the source afterwards,
you had to explicitly pass true to the constructor
or the TransformIterator would immediately end.
Now, the source argument is optional;
if an immediate end is desired, pass an empty source.
Simplified & generalized data-metadata split and adjusted tests
Merge branch 'enhancement-metadata-check' into 'master'

Enhancement metadata check

See merge request !8
Added followRedirect parameter to http client
Add generic options to request.
Remove obsolete jsdom dependency.
Merge branch 'feature-redirect'