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

* This updates all references to nuget.exe to use the copy in the root.
* This deletes all NuGet.config and NuGet.exe files that are not in the root.
* This removes all references to NuGet.targets (which is obsolete and no longer exists)

Check IsDefault of any ImmutableArray given for FixableDiagnosticIds, to ensure that it has been properly initialized.
Throw and InvalidOperationException to let the user know to fix their CodeFixer.

Move TestUtilities.csproj and TestUtilities.FX45.csproj to separate directories to accomodate current nuget limitations

Changes include:

1. Enhance CompilationWithAnalyzers to allow computing analyzer diagnostics for a specific tree/span within a compilation and/or for a subset of analyzers. Implementation ensures no duplicate analysis by tracking partial analysis state and caching the reported analyzer diagnostics.

2. Overview of the new APIs added to CompilationWithAnalyzers:
    1. GetAnalyzerSyntaxDiagnostics(tree, analyzers, ct)
        1. Analogous to SyntaxTree.GetDiagnostics(ct)
        2. Gets analyzer diagnostics reported by executing syntax tree actions on the given tree.
    2. GetAnalyzerSemanticDiagnostics(semanticModel, spanOpt, analyzers, ct)
        1. Analogous to SemanticModel.GetDiagnostics(spanOpt, ct)
        2. Gets analyzer diagnostics reported by executing rest of the non-compilation actions on the given tree span.
    3. GetAnalyzerCompilationDiagnostics(analyzers, ct)
        1. Gets rest of the analyzer diagnostics which are reported by either of the following means:
            1. Compilation actions (and compilation end actions)
            2. Non-compilation actions reporting diagnostics on different tree: Executing a symbol action on a symbol definition in a tree, can report diagnostic on its partial definition in some other tree.

3. Simplify IDE analyzer driver by switching it to using the new CompilationWithAnalyzers APIs for analyzer diagnostic computation. Both the IDE and compiler drivers now use the compilation event queue model for driving analysis.

The targets files were previously split into an open version in
Microsoft.CodeAnalysis.Toolset.Open and a closed version in build/. This
unifies the four targets into two new targets, VSL.Settings.targets and
VSL.Imports.targets, and moves all the targets from ..Toolset.Open into
the build/ folder.

Mechanically apply <Private>False</Private> to the newly-appeared
references.

This removes the majority of references to the deprecated Desktop
assemblies.  The only remaining ones are in the VSIX projects.  They
must remain until we actually delete the assemblies.

Upgrades System.Collections.Immutable to 1.1.34-rc and
System.Reflection.Metadata to 1.0.19-rc.

    - Adding code refactoring tests
    - Using the error logger for cases where there is not UI to show the user
    - Made sure the cookie registered with the IDE gets unregistered on close
    - Responding to general fixup comments

Updating the extension manager to report code-fix exceptions to the user. In Visual Studio this will cause an infobar to appear giving the user the option to either re-enable the crashing code-fix or re-enable it and ignore future crashes for that session of Visual Studio.

Updating the extension manager to report code-fix exceptions to the user. In Visual Studio this will cause an infobar to appear giving the user the option to either re-enable the crashing code-fix or re-enable it and ignore future crashes for that session of Visual Studio.

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.

This reverts commit b37052d0.

The BuildAndTest.proj was failing because a number of our suites aren't
correct when run in parallel.  Disabling them for now and letting #321
track reenabling them.

Remove CopyLocal from Microsoft.VisualStudio.Composition.Configuration references (changeset 1410325)

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

The EditorFeaturesTest.csproj file was pointing to the deleted References directory causing a git clone + build of Roslyn.sln to fail. Fixing up the project to point to DevEnvDir instead. (changeset 1408717)

The BasicIntellisense suite was broken due to a bug in BasicUndo.  This
was fixed in the most recent version.  Upgrading us to that to fix the
suite. (changeset 1408633)

Renamed resource, reverted TextEditorFeatures.csproj and added trailing newline back onto EditorServicesTest.csproj

resolves #38 by fixing typo in TextEditorResources and adding unit tests for SourceContainerExtensions

Bug-1116460 : Renaming the scripting assemblies and namespaces. Making corresponding changes in InstallDogfood and RoslynBuildAndTtest to account for new names (changeset 1408119)