Fix OutOfMemory issue.
Images copying implemented.
Remove ReplacementSpan properly after BackSpace.
Refactor: BaseRichTextWatcher architecture optimized.
Refactoring: handle spans replacement in one place.
Spans utility class added.
Refactoring: remove method copy from EffectsHandler.
Get span ordered while handling BACK_SPACE.
Git ignoring spec updated.
Merge pull request #3 from fstech/ddmytrenko/copy_images

Images copying implemented. Confirmed.