Test N3 formula serialization.
initNs and initBindings in SPARQLWrapper.update

Using initNs is implemented by adding declarations of the form
`PREFIX prefix: <uri>` to the beginning of the update.
initBindings is realised by adding the corresponding VALUEs at the
beginning of all WHERE blocks. Adding VALUE at the end of an update is
not possible. Since WHERE blocks must be used for updates operations
supporting variables and must not be used for operations not
supporting variables, this works out nicely, even if there are
multiple operations in an update.

This commit also fixes the Content-type and the name of the query
parameter for updates.
(See http://www.w3.org/TR/2013/REC-sparql11-protocol-20130321/#update-operation)
Improve bindings in SPARQLUpdateStore, add tests
Making test compatible with Python < 2.7
Merge pull request #292 from uholzer/sparqlstore-bindings

initNs and initBindings in SPARQLWrapper.update
Merge https://github.com/ericpeden/rdflib
Added ordering for QuotedGraph and GraphValue, graceful degradation for other sub-classes of node. fixes #291
bnode as public id for graph.parse. test + fixes #300.
test for #294
fixed tests for 2.5/2.6
Raise a ValueError if Graph.items is called with a recursive collection

Fixes a bug where, if a graph contains a closed/self-referencing chain
of rdf:rest statements, Graph.items would be caught in an endless loop.
Ensure quads added with addN have contexts that are a graph instance. tests and fixes #299
temporarily ping html5lib to 0.95 for py 2.6/2.7
pointer to update topic of #rdflib on release
minor cleanup
Merge branch 'master' of github.com:RDFLib/rdflib
make conjuctivegraph accept triples or quads for add/remove, preparation work for a fix to #307
Fixing __UNION__, this time in Graph.update

This has already been fixed in Graph.query, but noone thought about
Graph.update.
Setting default graph via URL parameter

SPARQL 1 and 1.1 both know the URL paramter 'default-graph-uri'. It can
is used to set the default graph of a query. Previously, when doing a
query on a context of a Conjunctive graph backed by the SPARQLStore, a
GRAPH clause is injected into the INSERT. Modifying the query is not
robust. Now, the default-graph-uri is set while leaving the query
unmodified.

The same is possible in SPARQLUpdateStore with the parameter
using-graph-uri, but it is not used by this commit, because it does
not work with my SPARQL endpoint.
there's no more reunification branch