Notification of string changes

Author: Tim Hunt
MDL-47494 gapselect: Bug fixes: #2009
1. Automatic display of right answer did not work if question text
contained images.

2. A choice of '0' was rejected by the form validation.

3. Hard coded strings moved to lang strings.


http://git.moodle.org/gw?p=moodle.git;a=commit;h=a719f4d218f92bca1e0f37700bf47c63d78dacc8
http://github.com/moodle/moodle/commit/a719f4d218f92bca1e0f37700bf47c63d78dacc8

+ 3.0 en [errorblankchoice,qtype_gapselect]
+ 3.0 en [errormissingchoice,qtype_gapselect]
+ 3.0 en [errornoslots,qtype_gapselect]
+ 3.0 en [errorquestiontextblank,qtype_gapselect]