Handle unsupported diagnostics reported by analyzers.

Fixes #252 : If an analyzer reports a diagnostic with an unsupported diagnostic ID, i.e. no descriptor returned by SupportedDiagnostics has that ID, then throw an ArgumentException in ReportDiagnostic method. This exception would be turned into an analyzer diagnostic by the driver and reported back to the analyzer host.

Also fix a few tests that were reporting diagnostics with unsupported ID!

Fixes #252 : If an analyzer reports a diagnostic with an unsupported diagnostic ID, i.e. no descriptor returned by SupportedDiagnostics has that ID, then throw an ArgumentException in ReportDiagnostic method. This exception would be turned into an analyzer diagnostic by the driver and reported back to the analyzer host.
Also fix a few tests that were reporting diagnostics with unsupported ID!

Sort nodes by location before determining contiguous spans encompassed b...

CommonSyntaxNodeExtensions.GetContiguousSpans() was incorrectly assuming that the supplied nodes will be in the order in which they appear in source. This helper is used in the analyzer that produces diagnostics to grey out unused usings (i.e. to produce one diagnostic for a set of contiguous unused using directives).

Due to the above incorrect assumption, we would end up producing a single diagnostic spanning multiple unused usings sometimes and multiple diagnostics at other times. Often different invocations of the analyzer for the same source file would produce different set of unused usings diagnostics.

While this does not cause observable problems in regular usage - this is a problem for tests and led to flaky behavior where test would pass sometimes and fail at other times.

VB EnC: enable editing methods with lambdas and LINQ - merged

Use TryGetValue when looking up cached SyntaxContexts

Use Unicode escape sequences for control characters

Make the IsLowPriority API take a cancellation token as well.

Changes to the syntax associated with BoundQueryBody caused slight changes in error span of some rarely reported errors. Update tests.

Conflicts:
	src/Compilers/CSharp/Portable/Syntax/SyntaxUtilities.cs
	src/Compilers/VisualBasic/Portable/Lowering/LambdaRewriter/LambdaFrame.vb
	src/Compilers/VisualBasic/Portable/Symbols/AnonymousTypes/AnonymousTypeManager_Templates.vb
	src/Compilers/VisualBasic/Portable/Syntax/SyntaxUtilities.vb
	src/Compilers/VisualBasic/Test/Emit/CodeGen/CodeGenClosureLambdaTests.vb
	src/EditorFeatures/VisualBasicTest/EditAndContinue/ActiveStatementTests.vb

Preserve Key modifiers from existing anonymous type properties

Fixes #1292

Make the IWorkCoordinatorPriorityService async and appropriately cascade out the asynchrony.

Originally this was synchronous because it was used through codepaths that all were
inherently synchronous.  Over the last year the WorkCoordinator has become increasingly
async, and we're now at the point where this API can be async too.  This is a win for
TypeScript because we have to currently implement this API in blocking fashion.  This
has shown up in profiles, and making it async should be a nice win for us.

Handle using static

Responding to PR feedback, fixing some typos and simplifying some of the
boolean logic.

Fixed crash in ValidateUnsafeParameters when binding lambdas for error r...

Make the portable ResultProvider DLLs portable

We created the CoreSystem projects to ensure that we wouldn't take
dependencies on non-portable APIs.  Now that the ResultProviders are
really portable, they enforce this requirement directly.

Prior to this commit, they were identical to the corresponding desktop
(i.e. NetFx20) assemblies but now all the pieces are in place to compile
them as portable assemblies.

Cleverness: Move resources into the portable projects and link them into
the corresponding desktop projects.  The desktop projects can compile
portable designer files, but not vice versa.

Make the EE-generated module name no longer fixed.

Fixes 1247

Handle the case where we are passed a type instead of a namespace (using
static).

Tie query nodes to their parent

Categorize synthesized query lambdas
Make sure SynthesizedLambdaSymbol and BoundQeuryLambda has the same syntax