This release contains breaking changes. If you use a custom ImageRegionDecoder, changes may be required to make it thread safe. For full details see the migration guide.

These changes are discussed on #120.

• Replaced setParallelLoadingEnabled with an option to supply a custom executor - setExecutor(Executor).
• Made AsyncTask.THREAD_POOL_EXECUTOR the default, to reduce contention with other background tasks.
• Removed synchronization of ImageRegionDecoder.decodeRegion calls to allow for parallel decoding by decoders that support it.
• Tiles are now loaded during gestures and animations instead of waiting until they end. This can be disabled with setEagerLoadingEnabled(false)
• Added experimental class SkiaPooledImageRegionDecoder which maintains a small pool of BitmapRegionDecoder instances to allow for parallel decoding when combined with a multi-threaded executor.