Add maintenance landing page with "We'll Be Back" message

	modified:   c2g/views.py
	new file:   templates/landing/static_landing.html
	modified:   urls.py
Merge branch 'master' of https://github.com/Stanford-Online/class2go into wescott-master-exercise-work
Merge pull request #1884 from Stanford-Online/wescott-master-exercise-work

Add maintenance landing page with "We'll Be Back" message
Fix for #1890

Only show confirmation if exam is NOT a survey and user hasn't answered
all questions

	modified:   templates/exams/view_exam.html
Merge branch 'master' of https://github.com/Stanford-Online/class2go into wescott-master-exercise-work
Merge pull request #1891 from Stanford-Online/wescott-master-exercise-work

Wescott master exercise work