Fix the gradle build..

gif decoder is being built as a sub project while other dependencies are acquired via maven.
Merge pull request #75 from kanelbulle/fix_gradle_build

Fix gradle build
Add override to request subclasses
Avoid NPE in multi transformation getId().
Fix safe key caching.
Don't memoize id in ImageVideoModelLoader
Allow puts of same resource to LruCache repeatedly
Add jar target and get AndroidStudio 0.6.2 working.
Fix android studio gradle build and lint errors.
Working auto import into intellij using pom files
Avoid allocating new object per default transform
Fix returning 0 size for GifBitmapWrapper
Pool and reuse GenericRequest objects.
Don't allocate ArrayList for single transformation
Don't allocate List for single cb in EngineJob.
Use priorities for requests fulfilled from cache.
Pool BitmapFactory.Options in downsampler.
Reduce some cache overhead in FlickrModelLoader
Add some logs for timing requests.
Only preload small thumbnails.