Fix up HTML CA tests

Changes to help speed up test suite for HTMLContentAssistProcessor
  - load metadata once @BeforeClass not @Before every test
  - split tests into unit versus integration. Any tests that involve setting up projects/folders/files/servers are now in integration suite. The rest are in unit suite.
  - Move away from actually generating files, indexing them, etc to do CA unit testing. Use an in-memory IDocument, wrap in a mock TextViewer, set up partitioning on that.
 
Allow using properties to control test suites run (so we can enable integration suite on nightly)