Allow switch for headless mode on any course page #2411

Once logged in you can now specify ?headless=1 to any page to go
into headless mode. To turn it off simply specify ?headless=0 to
any page.
Style changes for instructors

Style changes for instructors
https for fonts in main styles to stop https warnings
add pick up of site styles
Merge pull request #2497 from Stanford-Online/kluo-2411-headless

Allow switch for headless mode on any course page #2411
Merge pull request #2503 from dglance/dglance-instructor-styles

Style changes for instructors
Merge branch 'master' of https://github.com/Stanford-Online/class2go into giulio-tpg-report-2290