RIOT updates

[Andy Seaborne <an...@apache.org>]

I have just committed changes for the integration of the new webby 
reader into RIOT, together with moving it from org.openjena.riot to 
org.apache.jena.riot.

While I have tried to maximise compatibility by leaving some classes for 
basic usage patterns in  org.openjena.riot (and all deprecated), it's 
not a perfect redirection to the new world.

If any particularly inconvenient changes have got in, yell and I'll add 
some more compatibility code but generally apps don't call RIOT directly.

Code that does model.read is unaffected except that it will be using the 
content negotiation code, which includes guessing from file extensions 
and assuming no protocol means "file:"

A key new class is "RDFDataMgr" which has load and read operations for 
modeds, graphs, datasets and datasetgraphs in more flavours than is 
natural.  (default argument and implicit conversions would have been 
nice!)  This is a conceptual superset of the old FileManager (which 
still should work and hook into RIOT).

Still to do: documentation, examples.

	Andy