Merge pull request #14 from jklausa/master

Add section about reflection.
Add consistency to reflection
Fix inconsistent blockoquotes.
Merge pull request #15 from jklausa/master

Fix inconsistent blockoquotes.
Flow-sensitive optional unwrapping
Merge pull request #16 from radex/patch-4

Flow-sensitive optional unwrapping
Update README.md

Added **Abstract methods** and sorted table of contents alphabetically!
Merge pull request #17 from aleclarson/patch-1

Update README.md
Add enums nested in generic classes broken
Update for Chris Lattner's thoughts on systems programming features.
Merge pull request #18 from tanadeau/master

Systems programming features
Explains why Character semantics are meant to change
start Changed in Beta 4 section
Explains Character changes
Explains changes to access control
Revised Declaration Modifiers
Future changes to @-attributes
Merge pull request #20 from radex/patch-5

Changes in Beta 4
Added changes to how CGFloat works