Cocoapods 0.31.1 was failing this podspec because http://mixpanel.com returns a 301, not a 200
Use __unused to remove warnings as the variables can become unused if the NSAssert calls are preprocessed out in release builds
Reapply "xcode 5.1 warning fixes"

This reverts commit d949d3e153a2f98d2eadf88ffbd9f32d04c4f0af.
more casting to remove warnings
Merge pull request #120 from mixpanel/fix-podspec

Fix various warnings and podspec problems