Fix label not counting while UI Updates happening

NSTimers don't fire when user interface updates are happening, so the label will appear to skip numbers when embedded in something like a scroll view that's scrolling.
This changes from NSDefaultRunLoopMode to NSRunLoopCommonModes, which includes events coming in from the UI during scrolling
Merge pull request #9 from aweber/fixScrollAnimation

Fix label not counting while UI Updates happening
Added podspec.