Remove prefix additions
Add enumeration methodsi for NSArray

`- mappedArrayWithBlock` returns a new array by iterating through the
array and performing transformations on the objects
`-arrayBySelectingObjectsWithBlock` returns a new array by iterating
through the array and selecting objects that match the conditional
passed in to the block.
`-arrayByRejectingObjectsWithBlock` acts the same as the selection
method, but rejects objects that match the conditional instead