moved `resolveQName` and a few other functions to `Data.RDF.Types`
resolveQName returns a Maybe value instead of immediately failing when
unable to look-up the prefix
refactored t_qname
implemented `expandTriples`
exporting `expand*` functions
Merge branch 'robstewart57'

Conflicts:
	src/Text/RDF/RDF4H/TurtleParser.hs
added namespace expansion to other query functions
updated TODO
Merge pull request #19 from cordawyn/master

Triple, Node and URI expansion for TriplesGraph