Add progress feedback while unzipping (Android).
Add progress feedback while unzipping (iOS).
Use NSFileManager to determine fileSize.
Partially Revert "Add progress feedback while unzipping (iOS)." so that minizip can stay unchanged.
Merging PR #17: Adding support for progress events

Rebasing onto changes that Andrew added since the time of the patch.

Conflicts:
	src/android/Zip.java
Adding zip tests