removes blanks from quizdown multi-select

fixes #2416
travis IRC notification: fix yaml syntax, shorter templ
Merge pull request #2423 from Stanford-Online/jbau-no-blank-multiselect

removes blanks from quizdown multi-select
move fabric/cuisine from required to suggested

Until this becomes the main way to do this let's call those two packages
suggested.
Merge branch 'master' of https://github.com/Stanford-Online/class2go into giulio-share-results