Fixed BitmapProcessor interface
Pre-process images even if they won't be cached in memory
Removed deprecated ImageScaleType.POWER_OF_2 and EXACT.
Introduced ImageScaleType.NONE.
Introduced DisplayImageOptions.showImageOnFail(...)
Sample: Used DIO.showImageOnFail(...)
Issue #150 - Pass auxiliary Object to Display Options for
ImageDownloader
Refactored ImageDownloaders: made ImageDownloder as interface, created
BaseImageDownloader as default implementation
Sample: Use the latest lib snapshot