With https and reverse proxies, Piwik oftentimes uses absolute URLs (http://host/path/script).
Task is to use relative URLS (e.g., /path/script) throughout. This should eliminate the IE warning, "This page contains both secure and nonsecure items".
Also: refactor fix for #590.
(In ) fixes #691 - use relative URLs (except in Widgetize iframe & flash embed
code); refs #466 and #647 - should also resolve the reverse proxy issues
(In ) refs #691 - fix last step of installation
(In ) refs #691, refs #590 - fix regression with Flash over https with IE