Update wxWidgets to: wxGTK 3.0.1

From http://www.wxwidgets.org/:

wxWidgets 3.0.1 bug fix release is now available. Upgrading to it is strongly recommended for all users of 3.0.0 as it contains more than a hundred of important bug fixes to all ports but remains 100% compatible with 3.0.0, both at the API and the ABI level, and so upgrading to it doesn't require absolutely any changes to the existing applications.

So I hope it doesn't break anything.