Fixes #3456, added updating scheduled task for GeoIP databases w/ manager UI and easy-install for GeoLiteCity.

Notes:
  * Added new PEAR lib Archive_Tar and new Unzip implmentations for .tar.gz, .tar.bz2 & .gz files.
  * Modified Http class to allow use of Range HTTP header.
  * Added ability to download file in chunks to Http class.
  * Moved GeoIP admin page styles to separate CSS file.
  * Allowed monthly scheduled tasks to specify day of week to run on.


git-svn-id: http://dev.piwik.org/svn/trunk@7550 59fd770c-687e-43c8-a1e3-f5a4ff64c105