Super Global and forcing http/https

Updated Plugin to us EE's super global ee() instead of calling the instance on init.  Added set_ssl param to allow devs to force http or https for specific templates.  this comes in handy for when using engines such as nginx (while in apache doing this via htaccess is pretty straight forward).  however even with apache, this provides template level flexibility rather than having to edit htaccess files.

Signed-off-by: Jubair Saidi <jubair@savage-solutions.com>
Merge branch 'master' of https://github.com/jubairsaidi/http_header