isRunning method added at SDWebImageManager
Do not mark URLs a fail when error is due to missing network connection
Don't dispatch cancelAll calls. 

- should fix pre-fetcher problems #247
- cancelAll should be always called using the main thread
Merge pull request #268 from matej/prefetcher-fix

Don't dispatch cancelAll calls.
Merge pull request #260 from kawanet/master

isRunning method added at SDWebImageManager
Add imageFromMemoryCacheForKey: method to synchronously query the memory cache (fix #263)
Fix podspec (fix #253)
Fixed bug where NSInvalidArgumentException was thrown if an image with a nil URL was downloaded.
Removed creation of NSError when a nil URL is downloaded.
Merge pull request #274 from reidmain/master

NSInvalidArgumentException is thrown if a nil NSURL is downloaded.
Fixed CGBitmapContextCreate warnings for invalid alpha properties
Invalid cost calculation when saving image to memory cache
Merge pull request #278 from Reflejo/invalidcost

Invalid cost calculation when saving image to memory cache
Merge pull request #277 from Reflejo/upstream

Fixed CGBitmapContextCreate warnings for invalid alpha properties
Bump version to 3.1
Share framework target
Migrate the no longer github supported download page to a wiki page
Check SDWebImageCacheMemoryOnly for disk caching
Merge pull request #287 from NachoSoto/disk-cache

Check SDWebImageCacheMemoryOnly for disk caching
Revert "Fixed CGBitmapContextCreate warnings for invalid alpha properties"

This reverts commit 12196f4de69268dc994ba3d5bc04a11568177520.
It adds alpha on JPEG with no alpha.