Updated firefox and thunderbird packages fix security vulnerabilities

Several flaws were found in the processing of malformed web content. A web page containing malicious content could cause Firefox or Thunderbird to crash or, potentially, execute arbitrary code with the privileges of the user running it (CVE-2014-1574, CVE-2014-1578, CVE-2014-1581, CVE-2014-1576, CVE-2014-1577). A flaw was found in the Alarm API in Firefox, which allows applications to schedule actions to be run in the future. A malicious web application could use this flaw to bypass cross-origin restrictions (CVE-2014-1583). This update provides Firefox and Thunderbird 31.2, which fixes these issues and other bugs, and also provides several new features, including WebRTC support. The thunderbird-lightning package has also been updated to version 3.3 which is compatible with the new Thunderbird version. Also, Enigmail (part of the Thunderbird package) has been updated to version 1.7.2 which contains several bugfixes including mail with only Bcc recipients being sent in plain text unexpectedly (CVE-2014-5369).