SES-2014 added subjectResource, subjectURI, and subjectBNode convenience
methods to Model interface, and base implementations to AbstractModel.
SES-2039: now use GET method for remote SPARQL endpoints when the URL would be less than 8192 characters
SES-2040: re-introduced .setAdditionalHttpHeaders method
Merge commit 'f04e96140337ca8ea3f4f12db89b66dc9bb9e975' into 2.8.x
fix test compilation
SES-2040: as requested, now return a read-only view of the additional headers, and also check for null before setting the headers on the SparqlSession object
minor whitespace fix
SES-2040: avoid NPE if no HTTP headers are set and their value is requested
SES-2040: comment formatting
SES-2039: encode full query before checking it length
SES-2040 : Cleanup style, switch to Collections.emptyMap to avoid nulls

Null checks may be useful in some cases to check if there are any
settings, but it isn't a big deal in the general case case so we still
support nulls in the setters for backwards compatibility, but map them
to Collections.emptyMap internally.
Add more developers to contributor list in README.md
Merge branch 'SES-2039' into 2.8.x
SES-2022 : Change default to not verify datatype values

Change necessary to comply with RDF-1.1 Concepts that specifies that:

Implementations MUST accept ill-typed literals and produce RDF graphs from them.

http://www.w3.org/TR/rdf11-concepts/#section-Graph-Literal
SES-2022 : Fix tests and make fail on unknown work without verify set to
true
SES-2022 : Change to assertNotNull for two assertions that fail in maven

Still not sure what the solution is, but the assertions do not seem to
fail in Eclipse
SES-2043 : Check for JSONP before Accept to work with Chrome/Angular

Chrome, with Angular at least, seems to send Accept */* for JSONP
requests instead of the typical "application/javascript" and hence the
callback parameter needs to be checked before the Accept header to be
successful.
Merged in SES-2022 (pull request #267)

SES-2022 : Change default to not verify datatype values
Merged in SES-2043 (pull request #269)

SES-2043 : Check for JSONP before Accept to work with Chrome/Angular
SES-1880 : Add SPARQL 1.1 Service Description vocabulary