Removing 74x74 layer so icon loads on OSX 10.8.5.
Merge pull request #1 from cfarrow/enh-update-wx-2.9

Fix PDFgui for OSX in 64-bit mode.

This resolves startup crash, few more issues still remain (macports py27-wxpython-3.0 @2.9.5.0_0)
* poor resolution and spacing of toolbar icons
* missing toolbar on the plot windows