Refs #409

 * Deprecated setting, moved to JS API instead
{{{
; if set to 0, any goal conversion will be credited to the last more recent non empty referer. 
; when set to 1, the first ever referer used to reach the website will be used
use_first_referer_to_determine_goal_referer = 0
}}}
 * New setting to allow using 3rd party cookies for visitor ID cookie only
{{{
; Piwik uses first party cookies by default. If set to 1, 
; the visit ID cookie will be set on the Piwik server domain as well
; this is useful when you want to do cross websites analysis 
use_third_party_cookies = 0
}}}
 * Tracker uses 1st cookie values for Goals referrer attribution 
 * removed log_conversion.referer_idvisit field, unused

git-svn-id: http://dev.piwik.org/svn/trunk@3888 59fd770c-687e-43c8-a1e3-f5a4ff64c105