Bug Fixes and Condensing APIs

All issues associated with this milestone can be found using this filter.

Added

• Default value to completion parameter in downloadImage API in `ImageDownloader.
  • Added by Christian Noon.

Updated

• The Alamofire submodule to the 3.2.0 release.
  • Updated by Christian Noon.

Removed

• Superfluous APIs on ImageDownloader, UIButton and UIImageView extensions and replaced
  with default parameter values.
  • Removed by Anthony Miller in Pull Request
    #81.

Fixed

• Issue in UIImage extension where CoreImage filters were using the incorrect output frame.
  • Fixed by Felipe in Pull Request
    #78.
• All blur filter tests across all devices and OS's.
  • Fixed by Christian Noon.
• Issue where image response serializer was not thread-safe by switching over to
  thread-safe UIImage initializer.
  • Fixed by Christian Noon in Regards to Issue
    #75.
• Build warnings in Xcode 7.3 beta 2 for Swift 2.2.
  • Fixed by James Barrow in Regards to Issue
    #77.