Support configuring pprof HTTP server.

See http://golang.org/pkg/net/http/pprof/ for details.
Load buddy images from URL.

This allows the frontend proxy to cache images and avoids hitting the backend server too often. This also is required in preparation for further changes to move user data away from memory.
Get configuration from "mediaStream" service.
Remove user images on disconnect.
Load buddy images from "static" subfolder.
Use strong random number generator.
Added method to generate URL-safe random string.
Append filename to image url.
First path component when loading buddy images contains flags (currently unused).
Set width/height for buddy image (currently hardcoded to 46 pixels).
Set alt tag of buddy image to user name.
Only change update index if image actually changed.
Include timestamp of last change in URL instead of human readable update index.
Use 15 random bytes as image id so we don't get base64 padding.
Implemented top level controller layout configurations.
Removed obsolete code.
Update and evaluate caching headers when returning buddy images.
Added auto hide class to buddy list.
Hardcode buddy image resolution in template.
Make chat use new style layout object.