Created Issue: Installing Corlib package to windows phone project will cause unintallation error and asked to restart the project. [2877]

Repro steps:
1. create a new windows phone app
2. open nuget package manager dialog, search for atomic
3. install atomicphonemvvm package and then click install button to CorLib package

Expected: An error dialog saying The corlib package does not match the wondows phone 8.0 target framework

Actual: an error dialog says the following:

Successfully installed 'CorLib 0.0.6.27804'.
The process cannot access the file 'c:\Users\danliu\Documents\Visual Studio 2012\Projects\PhoneApp18\packages\CorLib.0.0.6.27804\lib\net40-Client\Corlib.dll' because it is being used by another process.
Successfully uninstalled 'CorLib 0.0.6.27804'.
Install failed. Rolling back...
Could not install package 'CorLib 0.0.6.27804'. You are trying to install this package into a project that targets 'WindowsPhone,Version=v8.0', but the package does not contain any assembly references or content files that are compatible with that framework. For more information, contact the package author.

4. now click Close button. Go to installed packages tab, click Uninstall atomicphonemvvm package

There is an error shown on the dialog, which says:
One or more packages could not be completely removed: CorLib.0.0.6.27804. Restart Visual Studio to finish uninstall