Add nullability annotations. Add @synchronized around UIImage creatio…

…n. Add check for error in the NSURLSession completion block.

2.0.1

Move NSString+JGAFSHA1 into the main class file to reduce the total n…

…umber of files.

Removes dependency on AFNetworking in favor of NSURLSession.

Fix implicit strong references to self inside blocks.

Update version number to 1.1.1

Add clearAllData method.

v1.0.2 beta release

Adds serial queue for saving to disk. Checks for free disk space available before saving to disk."

v1.0.1

Add retry logic.

add podspec file