forms in frontend automatically redirect to https
if automatic redirect to https was done automatically redirect back

if the user chooses https manually leave him there.

this is done by adding a cookie while the automatic redirect is done
use https for sessions
don't allow user logins without https
add support for server.httpsDomains setting

using that domains with certificate can be configured (in case not all have one)
set feAutologin cookie only for https if https is activated
add method that returns if https is supported and use it where appropriate
dynamically evaluate if https is supported
add second cookie for autologin that is not only set on https
add cache for requestHttps search
don't cache in preview
Merge branch 'master' into https-fe
don't redirect to http if session is started
destroy session after logout

- allows getting redirected to http
move code into public helper
add method that returns if a given domains supports https
only use https if domain supports it and component requests it
correct comment
for preview url use always https
Merge pull request #65 from nsams/https-fe

add full https support in frontend