Avoid re-loading UIKit for simulator drag.

PSTCollectionView depends on UIKit, so UIKit must be loaded into memory. Rather than finding the path and calling dlopen(), just search the existing symbols.
Merge pull request #349 from grpaul/patch-1

Avoid re-loading UIKit for simulator drag.
Merge branch 'master' of https://github.com/steipete/PSTCollectionView