SampleApp: Preview cardImage and support iPhone 6/6+

[cybertk]

[dgoldman-pdx]

@cybertk in general we'd like to keep our SampleApp very simple.

Could you please explain your reasons for suggesting these changes?

[cybertk]

The reasons are

• Current SampleApp does not support iPhone 6/6+. It displayed ugly on those newer devices.
• CardIO has CreditCardInfo.cardImage support, and I cannot preview this feature when I run pod try or start the Demo app from Xcode.

[josharian]

I'm definitely in favor of supporting the iPhone 6/6+. Thanks for doing that.

The cardImage feature is much less commonly used. I think I'm with @dgoldman-ebay on this one: I'd rather keep the sample app extremely simple.

Does your first commit (enabling iPhone 6/6+) work correctly if applied without the second commit?

[hkareemllc]

I second @josharian