Add "kpm wrap" command

- Add CsprojDumper, a tool used to dump csproj references
- "kpm wrap" creates project.json wrappers for csprojs in 'wrap' folder
- "kpm wrap" updates global.json to include 'wrap' folder as sources

parent #827 
This is a csproj, it cannot add `Microsoft.Framework.CommandLineUtils` as its reference.