Package Manager Console hook for ASP.NET 5 projects

[rowanmiller]

If a user is developing on Windows in Visual Studio, it's clear from dotnet/efcore#1196 that they still expect to be able to use the Package Manager Console with ASP.NET 5 projects.

The piece that's missing for us to light up the Entity Framework PowerShell commands on ASP.NET 5 projects is a hook to import our PowerShell module.

For *.csproj projects this is as simple as calling Import-Module inside of tools/init.ps1.

[yishaigalatzer]

Please talk to your friends in the DNX project.