Log Message:
Update to 31.7.0

Changelog:
Fixed in Thunderbird 31.7

    2015-57 Privilege escalation through IPC channel messages
    2015-54 Buffer overflow when parsing compressed XML
    2015-51 Use-after-free during text processing with vertical text enabled
    2015-48 Buffer overflow with SVG content and CSS
    2015-47 Buffer overflow parsing H.264 video with Linux Gstreamer
    2015-46 Miscellaneous memory safety hazards (rv:38.0 / rv:31.7)