Fixes #293. Bulk data is now created incrementally for the first time ever.

Pretty excited about this fix since it will reduce our bulk data creation times from something like 16 hours to something much less (I'm testing it now).

The new system looks for the old bulk files, if it finds them copies them over to tmp. From there, it opens up the files, adds or updates anything new and then swaps in the new versions. Much better than the previous method that rebuilt everything from scratch every time.