Merge branch 'release/1.5.3' into develop
Use ConcurrentDictionary for _writeTimestamps

Fix for issue #73
Extended LinqTests to test the DotNetRdfDataObjectContext class
Initial implementation of use of CONSTRUCT
Fixed CONSTRUCT query to use a subquery

This ensures all triples are returned for matching entities.
XDocument now kept as private variable

Ensures the ResultDocument property can be accessed multiple times when
it comes from a stream.
Test updates
Added changes for loading entities from triples sparql result, createt method to load data base on result type info
Merge pull request #75 from feugen24/develop

Changes and extensions to support binding custom SPARQL query results to dynamic objects and EF entities.
Extended LinqTests to test the DotNetRdfDataObjectContext class
Linq and SPARQL updates

Fixed LINQ query issues against generic SPARQL endpoints
Changed the SPARQL query builder to create a CONSTRUCT rather than a
DESCRIBE query to retrieve entities in full.
Fixed Convert.ChangeType call for mobile

Added value for IFormatProvider parameter that is required in mobile/PCL
Added NamespaceDeclarations helper and unit tests

Implements enhancement request on issue #69
Fixed variable name
Allow custom type mappings for EF context

Also renamed a few methods in EntityMappingStore to make it clear that
they SET a mapping rather than adding to a collection of mappings.
Added stubs for documenting advanced EF features
Fixed links to discussion group and API docs
Add support for user-friendly job labels
Extended existing unit tests to test job labels
Merge branch 'feature/job_labels' into develop