added a serial operation queue

added a serial operation queue that will be passed to UIImageView+LBBlurredImage to ensure that all blurs will be performed in the order they were called
add operation queue as message params

Added a operation to messages params to replace the GCD queue for a serial NSOperationQueue where the blur effect will be executed.
NSOperationQueueCode

NSOperationQueueCode
NSOperationQueue as ivar

Added an serial NSOperationQueue as ivar. This queue will ensure that all the blur effect calls will be performed in the order they were called improving the blur transitions.
Merge pull request #3 from yuriferretti/master

Improved blur transition