SVG minor fix

Updated sample SVG

Fixes luberda-molinet#980 - SVG: Improved USE element support & some …

…fixes

Fixes luberda-molinet#995 BlurredTransformation creates strange stria…

…ted effect on Android

Refactorings

Android - call RequestLayout when image size differs

Fixes luberda-molinet#925 luberda-molinet#907 - Some GIFs not working…

… properly on iOS

Added new sample CachedImageSizingTestPage

Memory cache enhancements

Fixes luberda-molinet#873 Xamarin.Forms - LoadingPlaceholder not alwa…

…ys shown on initial loading