Fixes #2667

 * Stop aggregating visits for Custom variables of scope "page"
  * still OK for scope "visit" since there is supposed to be one custom var value per custom variable name for a given visit
 * Now we always display the Actions columns so that these rows with no visit still show the number of Actions
 * cleaned up from custom var output report, removed some "price_viewed" column left out

UI Change (future FAQ maybe...)
 * When there is a "Visits" column for the Custom Variable report with a value of "-" (hyphen) then it means this custom variable was used with scope=page. 

Fixes #2662
 * Added integration tests testing getPageUrl with multiple periods and websites 
 * fixed a bug when idSite=all or 1,2,3

git-svn-id: http://dev.piwik.org/svn/trunk@5235 59fd770c-687e-43c8-a1e3-f5a4ff64c105