Kpm wrap update existing projects instead of creating new ones in wrap folder

parent #904 
Ah, I see! We do have some properties that we don't update if exist:
1. `version` property of project.json. If it already exists, we shouldn't overwrite it with the default version `1.0.0-*`
2. version of project dependency. If it already exists, we shouldn't overwrite it with the default version `1.0.0-*`

The value that a property above already has, is either default value `1.0.0-*` or user-edited value. So we should never update those properties.

But we should always update NuGet dependency versions and bin/pdb paths.

Fixed in the the latest commit. @davidfowl , thanks for patience :smile: