Implementation of `NSComparisonMethods` for iOS.
Dependant imports of categories for iOS support.
Since `NSObject` should not actually (iOS) respond to `isGreaterThan:` (EKGraph.m#91), changed edge weight to `NSNumber`. Can't see why it was `NSObject` in the first place.
Forgot dependant import in `EKBTree.m`.
Merge pull request #88 from aspcartman/master

iOS Support