Author: Damyon Wiese
MDL-44826 Atto: Image alignment options
If an image has custom alignment or margins - don't overwrite
them unless a new alignment option is chosen.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=d28af3d4aab83cb1f05d58ccb41057f159cdb7a0
http://github.com/moodle/moodle/commit/d28af3d4aab83cb1f05d58ccb41057f159cdb7a0
+ 2.7 en [customstyle,atto_image]