Upgrade tests to use Xunit 2.0
Remove app.config from Registry.
Prepare metadata reader tests to be portable
Build metadata reader tests as PCL
Re-enable some Vector tests which were flaky on CI machines
Merge pull request #259 from Priya91/registry

Remove app.config from Registry.
Merge pull request #263 from mellinoe/enable-vector-tests

Re-enable some Vector tests which were flaky on CI machines
Optimize ternary condition return
Merge pull request #268 from alfaproject/regex_ccek_equals

Clean up a line to avoid a ternary operator
Add System.IO.Pipes source code
Merge branch 'xunit2' into test_on_coreclr

Conflicts:
	src/System.Numerics.Vectors/tests/Matrix3x2Tests.cs
	src/System.Numerics.Vectors/tests/Matrix4x4Tests.cs
	src/System.Numerics.Vectors/tests/PlaneTests.cs
	src/System.Numerics.Vectors/tests/QuaternionTests.cs
	src/System.Numerics.Vectors/tests/Vector2Tests.cs
	src/System.Numerics.Vectors/tests/Vector4Tests.cs
	src/System.Reflection.Metadata/tests/TestUtilities/WorkItemAttribute.cs
Merge branch 'mdreader-portable-tests' into test_on_coreclr

Conflicts:
	src/System.Reflection.Metadata/tests/Metadata/MetadataReaderTests.cs
	src/System.Reflection.Metadata/tests/System.Reflection.Metadata.Tests.csproj
	src/System.Reflection.Metadata/tests/packages.config
Merge pull request #269 from mellinoe/add-pipes

Add System.IO.Pipes source code
Updated Readme to include Pipes

Added a short description of System.IO.Pipes to the readme list.
Update XML tests to register a code page provider

Required for the tests to pass on .NET Core.
Improve ActionBlock.Post perf for SingleProducerConstrained
Make SpscTargetCore.OfferMessage use Post method on fast path
Remove TargetCore.Post method as it doesn't add to perf.
Disable 4 PLINQ tests against GitHub issue corefx/240
Disable MetadataReader test against GitHub issue corefx/260