Analysis: Fix more warnings

Remove unused code, handle failures
Analysis: Add suppressions

Suppress ConOxide & awaitable issues, add dictionary words
Dependencies: Add basic dependency graph

Incomplete
Dependencies: Add ReaderWriterLock

Also fix parameter casing
Dependencies: Rescan single file
Dependencies: Extract VS-specific logic

Graph maintenance (& concurrency)
is now separate from VS project
system & editor handling.
Dependencies: Add VS event handlers
Dependencies: Expose completion for unit tests
Dependencies: Add basic test case
Dependencies: Fix test case
Dependencies: Add test case for new files

Doesn't work at all yet
Project: Fix reference paths

Remove duplicate <HintPath>s
Add <HintPath>s for EnvDTE to get doc comments
Dependencies: Fix new test case

Add more resilient ImportDirective reader
Dependencies: Update graph on file save

Doesn't work in unit test because listener is not exported to MEF.
Dependencies: Fix test graph MEF registration

Register new graph as IFileSaveListener to catch MEF broadcasts
Dependencies: Add basic dependent compiler invoker

Doesn't work yet
Dependencies: Fix chain compilation, add test case
Tests: Fix settings test for new defaults

Use setting which actually defaults to true to test migrations
Merge pull request #660 from SLaks/dependency-graph

Add LESS Dependency Graph