- cleaned up the Tracker/Action code, added tests, as well as cleaning up Actions archiving code

- now displaying all columns that user setColumnsToDisplay even if there are no values set
- displaying custom column names for downloads and outlinks tables
- enabled sort on download and outlinks
- it's now possible to sort a table by a column that is not defined. It will not error but just not do anything.
- fixed #393 Remove unique visitors from report for a given category of actions
- fixed #158 outlinks without subpages when there are outlinks with the same domain and subpages should be grouped in the same row
- fixed #535 Add "export" icons below the "Actions" reports (pages, download, outlinks)
- fixed #579 API Actions: full_url and url is 0
- REMOVED feature of naming an outlink or a download with a custom name. All downloads and outlinks are now grouped by the URL host. The data will be consistent across all 

periods independantly of the data set. Only data processed from this version will be affected.
- API CHANGE renamed entry_nb_unique_visitor in entry_nb_uniq_visitors and renamed exit_nb_unique_visitor in exit_nb_uniq_visitors in the Actions.getActions API call
- FEATURE outlink won't count clicks on URLs where the hostname is one of the registered hostname for this website (see Settings > Websites)
- FEATURE you can use Piwik to count clicks on links and count downloads, without using the automatic Javascript based download/outlinks tracking, but by modifying links to go 

through piwik.php.
  For example, http://yourwebsite.org/piwik/piwik.php?idsite=1&link=http://example.org&redirect=1
  will count the outlink in piwik and redirect the user to http://example.org
  For example, http://yourwebsite.org/piwik/piwik.php?idsite=1&download=http://yourwebsite.org/download.pdf&redirect=1
  will count the download in piwik and redirect the user to http://yourwebsite.org/download.pdf
 NOTE: it is recommended to rely on the automatic outlink and download tracking (more information on http://piwik.org/docs/javascript-tracking/). 
       rather than adding a depending on Piwik for your website to function properly. 
       However this feature is useful to some users as it gives a simple and reliable way of counting clicks, that you can then query using the Piwik API.


git-svn-id: http://dev.piwik.org/svn/trunk@1018 59fd770c-687e-43c8-a1e3-f5a4ff64c105