Only properties backed by instance variables are used for comparisons.

- [#1] Fixes recursive hash invocation due to Xcode 6 beta 4 making hash
a property.
- Subclasses that define non-ivar backed properties no longer hash and
do equality checks on those properties. These are computed and should be
redundant for computation.

Other changes:
- Updated cedar version
- Added spec suite for Xcode 6 beta 4 (test bundles are broken)
Updated README to properties used for equality changes
Updated podspec
Added ability to swizzle container methods for nice descriptions
Updated podspec