Pre/post block arrays should not be set publicly since there is no way to validate that contents are actually blocks
Remove JSONKit since we're 5.0+ now
Synchronize block array access, add capability for multiple completion blocks
Revert multiple completion blocks
Remove addCompletionBlock from interface
Remove JSONKit include
Merge pull request #58 from Raizlabs/ND-FallCleaning

Remove JSONKit, some block tweaking