SES-1861 : Localise repository connection objects and synchronize on
them

The repository connection object is localised to a request, but it may
be used multiple times within the request. By localising the
synchronized sections to where the actual RepositoryConnection API calls
are made, this chance is minimized, as there shouldn't need to be any
other locks at this level.
SES-1861 : Add tests for namespace updates
SES-1861 : Use ExecutorService to create a fixed thread pool
SES-1889 applied patch supplied by Dimitar
SES-1889 added compliance test to check bindings are sent when a HTTP
SPARQL update is processed in a (non-autocommit) transaction
Merged in ses-1889 (pull request #181)

SES-1889 bindings on SPARQL update as part of transaction over HTTP
Merged in SES-1861 (pull request #180)

SES-1861 : Add tests for deadlocking seen by user when updating namespaces using http-server