map async load correction

Loading asynchronously the map with the map sections initially
closed was not working with IE and FF (but Chrome was OK)
Forcing the document ready state does the trick (Extjs was loaded
into a DOM structure AFTER initial page load)

fixes #869
link protocol optimization

* use protocol relative urls when useful
* external urls that get automatically redirected to https use directly https
Merge branch 'master' into prod
Merge branch 'prod' of https://github.com/c2corg/camptocamp.org into prod