Add support for Windows Phone 8.1 project. The framework folder for it will be WindowsPhoneApp81 or wpa81
Add support for silverlight-based Windows Phone 8.1 apps by adding an alias for
framework WindowsPhone 8.1.
Add test coverage for portable targets including WindowsPhoneApp framework
Fix typo in VersionUtility._knownIdentifiers: WindowsPhoneAppa -> WindowsPhoneApp
Add some test coverage for wpa/WindowsPhoneApp framework identifier
Path to portable reference assemblies can be overridden with environment variable

If the NuGetPortableReferenceAssemblyPath environment variable is
defined, NuGet will use it as the path for portable reference assemblies
to load the profiles from instead of Program Files (x86)\Reference
Assemblies\Microsoft\Framework\.NETPortable.  This helps NuGet be used
from build machines where the portable reference assemblies aren't
installed.
WindowsPhoneApp framework support for JS
JS functional test fixes
Fix the bug that "nuget.exe push" will retry forever instead of asking for user's password
when NuGet.Server uses Windows Authentication.

Also a change to prevent infinite loop in RequestHelper.GetResponse() to guard
against current or future bugs that could cause infinite loop.
Fix of issue 3678: problems in XDT causes the target file to be truncated.

The cause is that we use XmlTransformableDocument.Save(targetFile).
However, if an exception is thrown during save, the content of the targetFile can
get lost.

The fix is to save the xdt transform result into a memory stream first, then save
the memory stream into the target file. This way, if there's any problem with xdt,
the target file won't be touched.
Fixes #4021 by rewording the reinstalling-packages message
Update the version number to 2.8.1
FrameworkName null check
Fix the problem that the web request is displayed twice when -Verbosity is set to detailed.

The cause of the duplicate output is the change to fix issue 3801 (which
was caused by incorrect use of the weak  event handler pattern). With
that fix, the SendingRequest handler will be called twice. The fix is to
use the weak event handler pattern here too.
Fix the problem that package restore doesn't work with VB or F# projects.

The problem is that when called from VS, when evaluating Exists() condition, the path
relative to the targets file, instead of relative to the project. Note that this
problem doesn't happen for C# projects, nor when you're using msbuild directly.

The fix is to use absolute paths.
Additional FrameworkName null checks
Update Microsoft.Web.XmlTransform.dll.
Fix of issue 4001: Automatic Package Restore should not be tied to activePackageSource.
Revert "Update Microsoft.Web.XmlTransform.dll."

This reverts commit f3b4ae4569d53274cdf857fa576f0eb263bee7ec.
Created powershell method CreateTestPackage and removed file PackageCreator.cs.