Breaking Changes

• Remove FullMatcherFunc. Use Matcher or MatcherFunc instead. More
  breaking changes around the protocols will probably occur in the future.

Features

• beEmpty() supports NSIndexSet
• Expose stringify() which Nimble matchers use to convert values to string.
  • You can add custom support to stringify by conforming your type to
    TestDebugStringConvertible

Bug Fixes

• Fix bug where exceptions weren't properly caught for cocoapods users
• Resolve warnings for Xcode 7.3