VBSP now check all search paths for FGD files

VBSP will now check all search paths for FGD files when using
func_instance
Fix for custom URL handlers in vgui::HTML panel

Custom URL handlers for the vgui::HTML panel now pass the URL and protocol
Added auto-complete to the give command

Auto-completion has been added to the give command. The classnames that
begin with item_ and weapon_ have been added to the autocomplete too.
Missing Visual Studio extension in gitignore