Updated to use the new target framework in project.json
Made k10 and aspnetcore50 work together
- Changed KRuntime to use aspnetcore50
- Added tests for compatiblity between k10, aspnetcore50, aspnet50 and net45
- Make it so that it's possible to consume aspnetcore50 packages/projects from k10
add --native option to kpm pack which will crossgen all dependencies in the output
Response to code review

* Rename Microsoft.Framework.Project to Microsoft.Framework.ProjectManager to avoid conflict with Runtime.Project
* Move IsCore method to VersionUtility