If you reject pull request https://github.com/piwik/piwik/pull/161 for the master branch (i.e. Piwik 2.0+), you may still want to consider these updates for Piwik 1.x (1.13 going forward).
Piwik 1.12 currently doesn't recognize IE11, Windows 8.1 and Maxthon. Opera versions 15+ are wrongly identified as Google Chrome.
I trust you have tested well the code as I haven't.
Thanks for the Pull request!