Fail CMake if building WX without GTK libraries.
FrameAui: Allow notebook tabs to be rearranged in the parent notebook.
Merge pull request #1526 from rohit-n/build-wx-gtk

Fail CMake if building WX without GTK libraries.
Merge pull request #1531 from lioncash/notebook

FrameAui: Allow notebook tabs to be rearranged in the parent notebook.