Update pager to include +- 5 pages
Species is no longer a required field
Split each verification step into subjobs

It seems like the way django works it doesn't always release memory when
you might expect it to. By limiting the job size it keeps the memory
footprint small while also allowing multiple upload threads to be used.
Fix a race condition with celery

The celery worker would sometimes kick off before the ImportEvent had
been saved. When it was saved it would result in a duplicate key
error. To solve this we manually commit the transaction before calling
any celery tasks.
Add status field
Add in better list view
Execute blocks of verification/commits

Instead of committing everything at the same time, work on blocks
"BLOCK_SIZE".

This should make it easier to run parallel updates
Update tests
Merge pull request #114 from ahinz/topic/more-importer

Topic/more importer