add apache redirectors (#1817)
Default Hide Answers button to disabled in in-video exercises

	modified:   templates/exams/videotest.js
	modified:   templates/exams/view_exam.html
environment example: fix comma typo (#1817)
apache redirectors, small fixes (#1817)

- make redirectors optional, not req'd for dev/staging for example
- typo in template
Merge pull request #1822 from Stanford-Online/sef-1817-redirect-dbclass

Apache redirects to handle db-class.com and db-class.org (#1817)
Complete fix for #1783

Check that user has at least something for each unique named element
or group of elements in a form

	modified:   templates/exams/view_exam.html
Merge branch 'master' of https://github.com/Stanford-Online/class2go into wescott-master-exercise-work