Fixes #319 redirects from http to https are not followed.

Fixes #367 Serving ontologies from github as well.
Fixed #269 single anonymous individual split in two on save to RDF
Fixes #348 ManchesterOWLSyntax round trip problem with disjoint classes

See the bug report for full information on the multiple issues going on
here.

Fixed here:
- missing rendering of DisjointUnionOf
- wrong parsing of DisjointClasses with extra entity
- missing parentheses around class unions
Added method to OWLOntologyLoaderConfiguration to disable cross protocol
redirects on URLConnections.

URLConnection by default follows up to five redirects on the same
protocol, but does not follow redirects across protocols.
Now following redirects across protocols is enabled by default, and can
be disabled through a configuration option.

Published interface change: extended OWLOntologyLoaderConfiguration.
Improved redirect following