Remove app.config from Registry.
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 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 build to be more consistent no matter how you build it.

This is the initial change to switch to using common targets across the repo.

This change adds a dir.props and dir.targets file that each project file will
import at the top and bottom of the project to default a lot of the common properties
and targets.
Update the newly added projects to import dir.props/dir.targets.
Clean up some of the dir.props and dir.targets files.

Add a VerifyBuildTools target to dirs.proj to ensure check for build tools
before trying to build. I tried adding something similar to dir.targets but
there was some issues and it seemed to cause some perf hits checking in ever
project build. If we find that we run into issues we can reconsider adding that.

This change also updates build.proj to add a semaphore file to use to detect
if build tools have been installed or not.
Add dir.props/dir.targets to all the test projects and enable building them.

Added */tests/*.csproj file to dirs.proj list of projects to build.

There are some tests like the MetadataReaderTests that build against desktop
framework and so that project needed some hacking to get the correct props used,
we should fix that at another point.
Rename the System.Linq.Parallel test folder from "test" to "tests" to follow
the convention.
Remove mscorlib reference from System.Linq.Parallel.Tests.csproj.

The mscorlib reference is no longer needed as it is automatically added
by dir.targets now.
Clean up some project files for to improve consistency and spacing.
Remove the old TFS source bindings from the props file as it isn't needed with git.
Fix System.Linq.Parallel.sln file after move of the test project.
Switch to importing dir.props/dir.targets using GetDirectoryNameOfFileAbove.

This commit also updates the new System.IO.Pipes.csproj to follow the pattern.