Also add usings when injecting a known dependency (VSIX-48)

[Piedone]

Originally by @barthamark.

The issue is, what to do when a dependency is available both in Orchard 1.x and Core, like IClock?

Jira issue

[barthamark]

Using something similar what VS does when typing a class name and suggests the available class names from even packages would probably help since it would also add the using as well. Related: #9 (comment)