integraton test for deactivating highslide when Shashin is upgraded
update readme for 3.3
throw an exception is set() is called with an invalid argument
don't load prettyPhoto if the user has selected that option
add prettyPhotoLoadScript settings; simplify updateSettings()
add prettyPhotoLoadScript to settings menu
ignore unrecognized shortcode attributes
add deactivateHighslide() as a pre-upgrade hook, since Highslide won't work anymore
updated Shashin Photo unit tests