Factor out the include/import implementation.

svn path=/branches/quickbook-filenames/tools/quickbook/; revision=70029
Single action for import/include.

svn path=/branches/quickbook-filenames/tools/quickbook/; revision=70030
Missing copyright.

svn path=/branches/quickbook-filenames/tools/quickbook/; revision=70031
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 path=/branches/quickbook-filenames/tools/quickbook/; revision=70032