This change moves a good chunk of the IDE suites to be async.  This is
necessary in order for them to correctly pump and wait for tasks in the
STA environment.

MEF based approach had race issue where if aggregator created after source, aggregator will miss events fired before aggregator created.

Fixes #249: Fix IDE diagnostics test framework to use DiagnosticAnalyzerService to compute diagnostics rather than DiagnosticAnalyzerDriver.

This change serves multiple purposes:
1) Makes our test framework consistent with the IDE scenario in fetching diagnostics. We have missed out on multiple regressions where the core IDE DiagnosticAnalyzerDriver does the right thing and hence the tests pass, but the DiagnosticService in IDE does additional filtering and certain diagnostics are not reported in VS. This change should avoid such bugs.
2) Enable testing for diagnostics V2 engine work that JohnHamby is doing to merge IDE and compiler analyzer drivers. For this engine, there is no IDE driver and hence existing IDE diagnostics tests can't be run. This change should enable running IDE diagnostics on V2 engine.
3) Move a whole bunch of of test only code in DiagnosticAnalyzerService_Test.cs into the test layer.

Been almost a month since the code formatter was run so this change was
a bit larger than would be expected for a normal (weekly) update.  Diffs
mostly around:

- Whitespace changes
- Missing copyright headers
- Missing visibility modifiers

cleaned code little bit based on PR feedback

this is first step to add that support. added solution crawler progress reporter and renamed some types to solution crawler. and some plumbing to pass around progress reporter

cleaned code little bit based on PR feedback

this is first step to add that support. added solution crawler progress reporter and renamed some types to solution crawler. and some plumbing to pass around progress reporter

now it should properly re-tag editor when there are severity changes due to rule set changes or other changes. (changeset 1409269)