No longer include SlingShot build file. Also clean SlingShot build output as part of "clean" target.
No longer include SlingShot build file. Also clean SlingShot build output as part of "clean" target.

cgourlay/nantcontrib,cgourlay/nantcontrib,dahmage/nantcontrib,rmboggs/nantcontrib,cgourlay/nantcontrib,dahmage/nantcontrib,nant/nantcontrib,rmboggs/nantcontrib,nant/nantcontrib,dahmage/nantcontrib,rmboggs/nantcontrib,nant/nantcontrib