Initial Commit
The library provides a slider view for photos online.

Summary:
  The viewer hanles the downloading and caching of photos from the web, and display them with page controller.
User can browse the photos by flip forward and backward. Photos can be zoomed, panned and rotated according
device orientation.

Test Plan:
(1) In xcode run unit test
(2) DEMO application
Merge branch 'master' of github.com:do4way/DOPhotoViewer

Conflicts:
	.gitignore