Improved the Align enumeration

Replace the unique Align enumeration by 3 enumerations:

• AlignContent
• AlignItems
• AlignSelf

They all have different options, which make the API cleaner.

Plus:

• Removed the overflow() method for now.

addContainer() renamed addItem(), markDirty()

• Add missing markDirty() method
• ⚠️ BREAKING CHANGE: Renamed the method addContainer() to `addItem(). It is clearer that the added view is in fact a flex item, and not just a flex container.
  • Added by Luc Dion in Pull Request #8
• Add an implementation of the Ray Wenderlich Yoga Tutorial
  • Added by Luc Dion in Pull Request #7
• Add Swift 4.0 support

Initial official release

• Initial official release.
• Add unit tests

Initial beta release

0.1.1

Update doc + pod version