[FBU iOS] Tip Calculator - Review my app

[johnkriston]

My app is complete, please review. /cc @codepathreview @codepath

[sumade]

Good work. This prework is a preview of our weekly project process. Generally, weekly projects take between 5-10 hours to complete the required features and an additional 5-10 hours to complete the optional features. In general, we've seen that the more hours you log, the quicker you improve your proficiency with iOS. In particular, the optional extensions on each project are often the most valuable learnings since they dive deeper into common iOS use cases. We'll also be providing light code feedback for each submitted project once the program begins.

Btw, you can delete or close the other issues if you only want us to respond to a specific issue. Also, in the README, you can just put an "x" in the square brackets like this: [x]. This will automatically get interpreted as a checked box in github.

The purpose of this project was to begin to explore Xcode and to get a broad overview of iOS development using Swift. For example, in this project, we explored the following concepts:

• Code styling in Swift. You can find some code styling guides here:
  • Ray Wenderlich Swift Style Guide
  • Github Swift Style Guide
• Views are created in Storyboard, Interface Builder, or programmatically, but they have the same goal: instantiate, initialize, and layout view objects. We use IBOutlets to give names to view objects, similar to giving unique ids to divs in HTML.
• We registered for touch events, which can be done programmatically or via IBActions.
• View controllers have a set of methods that are called when it loads, appears, or disappears. These are called view controller lifecycle methods.
• Do your views look good on iPhone 4, 5, and 6? Do your views look good on both iOS 6 vs iOS 7/8? We will cover in class how to use Auto Layout to robustly design your views for different screen sizes and OS versions.
• After this assignment, you should understand the purpose of IBOutlets and IBActions as well as the basics of designing views and programmatically interacting with the views from the controller.