[FIX] prevent default for mousedown image to prevent ie and ff must set the new range

[FIX] prevent default for mousedown image to prevent ie and ff default 'features' must set the range because the cursor is used for edition. Warning for picture because the browser can't target the image but the container.

Using range instead of $target, it is not necessary to memorize $target if the range is properly distributed
Modify the code to use the dom range.