Use the same threads per CPU limit DNX uses.

Moved many APIs to async which contained wait calls.  Forces developers
to use async now in tests when appropriate.

The casing of app.config was incorrect in several of the project files.
This broke tests on Linux / Mac.  Corrected the case.

Updating System.Reflection.Metadata to 1.1.0-alpha-0015 and System.Collections.Immutable to 1.1.37.0

Revert "Updating System.Reflection.Metadata to 1.1.0-alpha-0015 and System.Collections.Immutable to 1.1.37.0"

This reverts commit d78dbb97.

Updating System.Reflection.Metadata to 1.1.0-alpha-0015 and System.Collections.Immutable to 1.1.37.0

Updating Microsoft.DiaSymReader to v1.0.6, Microsoft.DiaSymReader.Native to v1.2.0, and System.Collections.Immutable to v1.1.37

Naming the execution scripts 'csc.sh' and 'vbc.sh' is counter to the
convention of not using any extension on *nix executables. While the
scripts are not strictly executable programs, they are meant to be
transparent shims around the actual execution of the compilers on *nix

After updating to the latest CoreCLR NuGet packages we no longer need to
be copying binaries from a drop share to run. This change adds a csc.sh
and a vbc.sh so we can run on the CoreRun host on Linux like we do on
Windows. The change also eliminates some cruft from the cibuild like the
semaphore restore.

Update to a new version of the Roslyn Diagnostics analyzer package.

The -f option doesn't include files that don't already exist, while the
-u option updates existing files and also adds files that don't exist.

Also, we were deleting the zip file after unzipping, leading the caching
to always fail and download new zip files every time, so this should
allow caching to work again.

Right now we parallelize by sticking multiple mac builds on the same machine. Since NuGet and Mono toolset restores are machine-global, sometimes the builds stomp on one another. This adds a semaphore to only allow one build to restore at a time.

Updates the mono toolset to mono built from source at tag
mono-4.2.0.207.

Updates the mono toolset to mono built from source at tag 4.2.0-207.