Switched some NSAutoreleasePool calls to @autoreleasepool as per https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSAutoreleasePool_Class/Reference/Reference.html#//apple_ref/doc/uid/20000051-1722
Merge pull request #333 from josh64x2/autoreleasepool-improv

Switched some NSAutoreleasePool calls to @autoreleasepool