Fix warnings, update podspec
Add OS X support
Merge pull request #8 from sirwart/master

Add OS X support
Can now include Visual Format Language strings with addCompactConstraints:, since they can be unambiguously distinguished from CompactConstraint strings
Allow priority to be specified in constraints

This extends the format to add an optional "@ priority" to the end, pulling
the values as either doubles or values from the metrics dictionary.
Add `priority` documentation to README
Fix README typo
Merge pull request #9 from bencochran/priority

Allow priority to be specified in constraints
Merge commit 'cb5642abba94c4290bbd86a1ad0909ea488784b8'

* commit 'cb5642abba94c4290bbd86a1ad0909ea488784b8':
  Fix README typo
  Add `priority` documentation to README
  Allow priority to be specified in constraints
  Can now include Visual Format Language strings with addCompactConstraints:, since they can be unambiguously distinguished from CompactConstraint strings
  Add OS X support
  Fix warnings, update podspec

Conflicts:
	CompactConstraint/NSLayoutConstraint+CompactConstraint.m