fastbulk - Adjustments to fix various issues (2)

fastbulk - Adjustments to fix various issues (2)

* Use tmpfs for /usr/obj, this speeds up builds by a lot.
  make w/ -DNOTMPFS will use the hard drive if your tmpfs
  isn't big enough.

* Cleanup {chroot}/tmp/logs/run/* when restarting

* When restarting handle the case where the correct package has
  already been installed.

* When restarting handle the case where the binary package already
  exists.

* Use pkg_add -f when adding existing packages.