Factor out the include/import implementation.

[SVN r70029]
Single action for import/include.

[SVN r70030]
Missing copyright.

[SVN r70031]
Use version switch for new include/import functionality.

I didn't mean to check it in. But now I have, let's pretend it was
deliberate. Not finished yet, and I should be dealing with other things
at the moment.

[SVN r70032]