unable to install SimpleStorage for shared project

Hi,

I was not able to install the SimpleStorage under nuget, for the shared project.
The error message is as follows (also in attached screenshot):
Could not install package 'SimpleStorage 1.3.1'. You are trying to install this package into a project that targets 'portable-net45+win+wp80+MonoAndroid10+xamarinios10+MonoTouch10', 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.

1. I could install it for the Android and iOS code though.
2. I am using VS2013 running on mac.
   Thank you in advance for your kind assistance here.