contrib/php-collection: Save/load graph list and fix HTTPS handling.

contrib/php-collection: Save/load graph list and fix HTTPS handling.

Hi,

An update to the graphing interface. (incremental patch attached)

This fixes security complaint by a few browsers when page is accessed
via HTTPS and also makes sure the graphs and lists will load if HTTP
and HTTPS paths differ.
Thanks to Mullet- for spotting this issue.

In addition to the fix above this patch adds support for saving
current graph list to a cookie and appending graph list read from
cookie to the currently displayed list.

A future extension would be to allow saving/loading named graph lists
so multiple list can coexist (pretty useful when monitoring multiple
servers/services)

Bruno