Once all #r methods are executed check the compilation to verify imports.
Do not call import if the namespace does not exist within compilation.

Do not Build.Cancel if build has already completed.

The reason for these have been lost to the sands of time. Let's delete
them.

Base selection on the currently opened Document

Changes behavior of send to REPL when no selection is present.
In this case selects the line under caret.
When this line is invalid syntactically expands the selection to a valid
parent syntax node.

...by ensuring that these assemblies take at least 10 seconds to run.

TODO: revert this change.

NOTE: the usual workaround - disabling appdomain creation in xunit -
doesn't work in this case because of assembly loading issues.  See #7976
for details.

ResetInteractive base class is not coupled to VS and therefore is much easier to test.

Clobbered by rebase.

...and a host object property on InteractiveScriptGlobals.

This is a first cut and my main goal at this point is forward
compatibility.  The existing unit tests all pass.

TODO: Make some improvements to the existing behavior.
TODO: Update the existing test baselines.
TODO: Introduce new tests.

This branch should be buddy testable - tweak the existing formatter by
subtyping (e.g.) `CSharpObjectFormatter` and assigning an instance of your
subtype to the global `ObjectFormatter` property.  It should be consumed
by subsequent submissions.

by removing `<DebugType>` lines from projects that import `VSL.Settings.targets`

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.

Ensured that all uses of app.config in our product / test code base is
used in the lower case form.  This helps with our Unix efforts where
mixing the case can be significant.  Updated all of the project
references to ensure they used the lower case version as well.

Add System.Runtime.Numerics to CsiCore and VbiCore dependencies, update CoreFX versions to the same as csc/vbc core

The scheduler returned by TaskScheduler.FromCurrentSynchronizationContext
does not allow concurrency (meaning all Tasks within a submission were being
inlined).  This would nearly always result in a deadlock if you kicked off a
child Task and attempted to continue within the same submission.

We can instead use the Winforms Dispatcher, which will invoke the parent
Task on the "UI" thread but allow child Tasks to use the ThreadPool.