Deprecation warning for deployment target set to iOS 7

Building `GrowingTextView` with Xcode 5 will issue a deprecation warning for `drawInRect:withFont:` when setting the deployment target of the project to iOS 7.0. I assume that you still want to support iOS <7, so instead of rewriting the code, I disabled the warning.

Also, I updated the example project to the settings recommended by Xcode 5.

Please merge - thanks