#406 - Fixed a problem where hitting a failed URL more than once wouldn't call the completion block
Merge pull request #408 from dlbuckley/issue-406-Failed-URL-Problem

#406 - Fixed failed URL problem
Custom image cache search paths

This is particularly useful if you are bundling images with your app that have been cached by SDWebImage. (ie. if you are 'seeding' your app with a core-data file that contains a lot of URL's to images and would like to also seed those images without having to copy every one of them over)

For example, you can tell SDImageCache to add '[[NSBundle mainBundle] resourcePath]' as a custom path, so that the main bundle will be queried for cached images.

This prevents the need for you to copy pre-cached images over to the caches/ImageCache folder that SDImageCache normally checks for.

The custom paths are read-only.
Refactor GIF support

Remove GIF specific code from main source, isolate it in a UIImage category to ease future addition of format support
Add WebP format support (fix #410)

How awesome is that?! =)
Added libwebp dependency. Also fix a typo in description.
Merge pull request #413 from stylight/master

Fixed dependency on libwebp in the podspec
Do not enable webp when not explicitly activated by a macro (fix #415)
Make sure setNeedsLayout gets called on the main thread