joomla/joomla-platform — pull request #839 by oc666 (2012-02-08 10:07:38+00:00)
Title: add curl and socket to update process of Joomla

Due to requests of users to be able update joomla when allow_url_fopen is block (bug tracker #27852 & https://groups.google.com/forum/#!msg/joomla-dev-framework/lP1ql5K8Rdw/ZuVRB8JL_SAJ), this pull request add the ability to use curl & socket.
The pull request change the way the update communicate, and it's using the new JHttpTransport layer of the platform.
The default prefer way to transport is curl and it can be change (see JUpdater::getAvailableDriver).
I've added isAvailable method to JHttpTransport interface, and each sub-class implemented this method accordingly (include in the pull request).
Please review.