Lib need autorelease pool

During development i`ve found that with large amount of archive to unzip (in loop) app memory start to accumulate some unzipped data, and release only after loop is gone.

So i run several times two simple tests.

Input:

Zip Archive, size 2.2 MB
Unzip times: 75

Without autorelease pool: http://cl.ly/image/1m0S1R1s0b0g
With autorelease pool: http://cl.ly/image/0y04212X1k2U

I propose to add my minor changes (or do it yourself).

My point: 

For apps working with large amount of files accumulating memory is evil, and easily results to crash old devices with memory warning.

Sorry, for my english.

Regards.