Add indices on Actions table.
Improve Actions indexes.
Merge branch 'master' of github.com:jsha/blocktogether into actions-index
Merge pull request #101 from jsha/actions-index

Add indices on Actions table.
Trim old blocks

Call destroyOldBlocks in finalizeBlockBatch to remove all but two latest
BlockBatches for user when a new BlockBatch is retrieved successfully.
Call destroyOldBlocks with uid instead of BtUser object
Merge pull request #100 from BooDoo/issue/59/trim-old-blocks

Trim Old Blocks
Merge remote-tracking branch 'jsha/master' into block-diffs

Conflicts:
	update-blocks.js
Improve verifyCredentials log line.