SES-1723 : Fixed duplicate display of statements where subject, predicate and/or object matched.

* Added a regression test and several new unit tests for reproducing the issue.
* Removed servlet duplicate checking code's dependence on SPARQL, simplifying the code.
* Refactored the SPARQL Update code in the tests to make adding statements more compact.
SES-1741 : Directly recursive federation creation prevented at Federator level.

However, Workbench code should stop it from getting this far, just like the Console does.
SES-1741 Create Federation now disables create button if fed id matches any existing.
SES-1741 : Proper warning display whenever fed id matches existing.
SES-1741 : Improved location, behavior and consistent styling of warning messages.
SES-1721 : Added testGetNamespace to RepositoryConnectionTest

Also removed some unused variables, and fixed a deprecated method call.
Merged in dvisser/sesame/SES-1723 (pull request #74)

SES-1723 : Fixed duplicate display of statements where subject, predicate and/or object matched.
SES-1741 XML formatting fix
Merged in dvisser/sesame/SES-1741 (pull request #75)

SES-1741 Fix allowing federated repositories to have the same id as members
Merge branch 'master' into SES-1721
SES-1721 Addressed reviewer suggestions, and most PMD warnings.
Merged in dvisser/sesame/SES-1721 (pull request #76)

SES-1721 : Added testGetNamespace to RepositoryConnectionTest