1. Drop "is" for some names
2. CommentBlock -> BlockComment

Plus a little clean up.

Now, Add-Using will use the indices if they have been built.  Or not search
those projects/metadata if they're not available.

Note: this doesn't change any of the searching of the current project.  That
works the same way it always has.  This is only for searching unreleated projects
and metadata dlls.

Moving common code to AbstractDirectiveTriviaBraceMatcher

Ensure that suppression state for build diagnostics shows up as active instead of <blank>, and build diagnostics are not suppressible from error list, i.e. "Suppress" menu does not show up in the error list.

Fixes VSO [#164642](https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems#_a=edit&id=164642)

This reverts commit c25f2528.

Fixes #873

Sometimes there are buffers with our C#/VB content types that are not added to the Running Document Table and therefore never end up in the MiscellaneousFilesWorkspace (or any workspace), such as the Source Control "Annotate" view. This change updates the Syntactic Classifier to handle such cases by parsing its initial snapshot for tagging (changes are not observed, but the known use cases of this fix are uneditable anyway).  There are some exceptions to this behavior (e.g. the Immediate window) which require us to go digging through attached views, but we default to classifying these buffers now.

Conflicts:
	src/EditorFeatures/Core/EditorFeatures.csproj

We don't need SolutionDir or RestorePackages, which were for very old-
style restore systems.

Update 1 defaults to copying implementations for some class libraries, but we
don't need that for our feature binaries.

No longer call SetSynchronizationContext just to get Dispatcher-based TaskScheduler.

This change makes foreground scheduling code predictable in the IDE
tests.  Instead of using a static to hold the data we use instance
values.  The static data the instance values are populated from are not
100% predictable but far more so than they used to be.

Add an interface, ICustomCompletionItemFormatter, that when implemented by a CompletionListProvider, is called to format the CompletionItem.

But report a non-fatal watson so we can try to track down what outlining service caused the problem.

This behaves more or less exactly the same as IGoToDefinitionService.

* 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)

Add a new suggested action "FixMultipleSuggestedAction" for IDE layer corresponding to FixMultipleCodeAction and FixMultipleContext. Also implement the FixMultipleOccurrencesService to compute and apply a FixMultipleSuggestedAction.

Subsequent change will use this service to fix (suppress) diagnostics selected in the error list.

Provide a special buffer tagger for accurate tagging of classification in the copy/paste and printing scenarios.

Additionally, the IsDebugger and IsImmediateWindow properties have been removed from CompletionTriggerInfo. Any code that was checking these properties now checks for options that are set by the Controller in debugger scenarios.

We need a way to provide alternate completion in the Interactive Window.
Previously, we weren't taking TextViewRole into consideration when
selecting completion providers.  This change allows a service to opt in to
considering TextViewRole by passing OrderableLanguageAndRoleMetadata to
SelectMatchingExtensionValues.

This change also includes some cleanup of test helpers and removal of extra
TextViewRole attributes that weren't doing anything meaningful.

This change does two actions to our public API files:

- Resets them to the versions from 1.0.0 RTM
- Splits them into the shipped and unshipped files