$translate.instant is not using the return value of the missingTranslationHandlerFactory

$translate.instant() did not respect the return value of the missingTranslationHandlerFactory, resulting in the translate filter and $translate.instant() always returning the translationId instead of the value returned by the missingTranslationHandlerFactory
Looks good to me and should work. But could you please provide a test case on this element also?

Also, we should in this "patch" / release then fix or ... erm... implement the logic here 
 
https://github.com/mofux/angular-translate/blob/master/src/service/translate.js#L1146
https://github.com/mofux/angular-translate/blob/master/src/service/translate.js#L1187

also :-).