Temp fix for SMW\Test\QueryPrinterRegistryTestCase

Due to changes as to when test classes are loaded, some third-party
extension make assumptions about available test cases.

Removed SemanticMediaWikiTestCase dependency and solely
depend on \PHPUnit_Framework_TestCase

Only glanced over some of those tests but they need some serious re-factoring.
Merge pull request #310 from SemanticMediaWiki/fix-queryprinter-test-autoload

Temp fix for SMW\Test\QueryPrinterRegistryTestCase
Remove MediaWikiTestCase dependency

- Any change to the `MediaWikiTestCase` can potentially disrupt test scenarios.
- Introduce an independent `MwUnitTestDatabaseInstaller` that replicates the `MediaWikiTestCase` DB cloning procedure.
- `MwDBaseUnitTestCase` itself only relies on `PHPUnit_Framework_TestCase`
Remove MediaWikiTestCase from MwIntegrationTestCase
Remove MediaWikiTestCase from remaining tests
Merge pull request #311 from SemanticMediaWiki/less-mw-testcase

Remove MediaWikiTestCase dependency
Update RELEASE-NOTES.md
Move reporter related stuff to its own place

Add NullMessageReporter to remove unnecessary invocation during tests