Fix incorrect PARAM_TEXT.
CONTRIB-4557 make sure bg image is not re-sized

by bootstrap based themes.
Merge pull request #20 from jamiepratt/wip_CONTRIB-4557

CONTRIB-4557 make sure bg image is not re-sized
Merge branch 'master' of https://github.com/moodleou/moodle-qtype_ddimageortext