Suppress `Implicit conversion loses integer precision` compiler warning.

Hi mattlawer,
I got `Implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int'` compiler warning when I built BButton (without CocoaPods).

To get the compiler warning, Try the following steps:

1. Open BButtonDemo project on Xcode-6.1.1
2. Open `Build Settings` of BButtonDemo and change `Build Active Architecture Only` to `NO` (It required to ship the App to AppStore with 64bit binary. See http://stackoverflow.com/questions/26790554/ios-app-submission-missing-64-bit-support for more details.)
3. Build the BButtonDemo project

Regards