Make offline installer configs use 5.2.0 content

Change-Id: I0004a1842091592ab6624b216019935fbcd7cba8
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Add 5.2.0 release description file

Change-Id: I2de69046da087075ac102a87bd994f827e92a267
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Update update_repository.py script

Ignore deprecated config.xml argument. Accept the argument but do not
use it.

Added support for new repogen functionality: "--update-new-components".
Make the script more clever to update those components that have
version numnber increase only.

Change-Id: I21c573b472def6c7896ce0c911a56c0b1a0afeb0
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>