#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)
// Fix for issue #416 Undefined symbols for architecture armv7 since WebP introduction when deploying to device

Added Functions to resolve some undefined symbols when using WebP and force_load flag

void WebPInitPremultiplyNEON(void);
void WebPInitUpsamplersNEON(void);
void VP8DspInitNEON(void);

Changes under MIT License
Fix for issue #416 Undefined symbols for architecture armv7 since WebP introduction when deploying to device

Added Functions to resolve some undefined symbols when using WebP and force_load flag

void WebPInitPremultiplyNEON(void) {}
void WebPInitUpsamplersNEON(void) {}
void VP8DspInitNEON(void) {}

Changes under MIT License
Merge pull request #418 from dalexsoto/master

Fix for #416
Ensure we always set the UIKit image properties from the main thread (fix #403, fix #417, fix #398)
Change version to 3.3
Import WebP category only when the macro is activated.
Merge pull request #422 from BB9z/WebP_switch

Import WebP category only when the macro is activated.
Minor typo fix.
Merge pull request #423 from BB9z/superfluous-semicolon

Minor typo fix.
Add -calculateSizeWithCompletionBlock:.

This method provides a way to asynchronously calculate the size of the
disk cache, reporting both the number of files and the total file
size.

This is useful when querying large disk caches because the file system
enumeration operation can take some time.
Merge pull request #434 from jparise/calculate-size

Add -calculateSizeWithCompletionBlock:.
Remove an unused call to -callbacksForURL:.

We don't currently signal cancellation via a callback.