New command-line build and verify

This PR introduces a new command-line build and verify. Using `build.cmd` from a VS command line, in the root project folder, the following happens (by default):

 - the solution is built in Release and Verify configurations
 - in the new Verify configuration, code analysis, and msbuild 'treat warnings as errors' are enabled. CA ruleset is based on the 'Microsoft Managed Recommended Rules' from VS 2013. All enabled rules are set to error on violations.
 - Xunit tests are executed, reporting any errors

Sample output:
```
c:\My\repo\Humanizer>build
Microsoft (R) Build Engine version 12.0.30324.0
[Microsoft .NET Framework, version 4.0.30319.34014]
Copyright (C) Microsoft Corporation. All rights reserved.

  Humanizer -> C:\My\repo\Humanizer\src\Humanizer\bin\Verify\Humanizer.dll
  Running Code Analysis...
  Code Analysis Complete -- 0 error(s), 0 warning(s)
  Humanizer.Tests -> c:\My\repo\Humanizer\Src\Humanizer.Tests\bin\Verify\Humanizer.Tests.dll
  Running Code Analysis...
  Code Analysis Complete -- 0 error(s), 0 warning(s)
  Humanizer -> C:\My\repo\Humanizer\src\Humanizer\bin\Release\Humanizer.dll
  Humanizer.Tests -> c:\My\repo\Humanizer\Src\Humanizer.Tests\bin\Release\Humanizer.Tests.dll
  xUnit.net MSBuild runner (32-bit .NET 4.0.30319.34014)
  xunit.dll:     Version 1.9.1.1600
  Test assembly: c:\My\repo\Humanizer\src\Humanizer.Tests\bin\Release\Humanizer.Tests.dll
    Tests: 3619, Failures: 0, Skipped: 0, Time: 0.845 seconds
```

This is based on the [Albedo project](https://github.com/ploeh/Albedo). I removed the nuget and versioning-related tasks. They could be added back if needed.

// cc @moodmosaic - would appreciate your feedback, if you can :)