Don't import posts that have already been imported.  If a user exists with an imported username, attribute things to that user.
Don't import posts that have already been imported.  If a user exists with an imported username, attribute things to that user.

git-svn-id: d0e296eae3c99886147898d36662a67893ae90b2@1319 653ae4dd-d31e-0410-96ef-6bf7bf53c507

dragonmantank/Habari,dragonmantank/Habari,dragonmantank/Habari