RuntimeClient: Add exec() method.

Handy shortcut to safely invoke runtime extension methods.
FileReader: Use exec() instead of long and ugly direct calls.
Image/ImageView/XHR, Flash: Use OProgressEvent.
Image, Resample: Add.
Image: Switch to this.handleEventProps().
Image, HTML5: Make use of resampling algorithms.

Very slow, almost - unusable. Need to try WebWorkers.
Image, HTML5: Decrease factor to 0.6 (0.8 is too slow).
Image, HTML5: Do not use pyramid downsize for nearest neighbor resampling.

Doesn’t have any effect anyway.