Float canvas updates

[ChrisBarker-NOAA]

Fixed few bugs for newer wxPython, numpy and Python.

Tested with:

• Python 3.10
• numpy 1.25
• wxMac OS-X 11.7.9

Fixes #2320, #2331, #1824

Also got many of the samples working, and cleaned up a bunch of formatting.

I only touched FloatCanvas code.

[ChrisBarker-NOAA]

NOTE: I was getting segfaults on exit if there was a wx.Overlay still around. But having it deleted in a del method didn't do it -- I had to do a real kludge to fix it -- see:

floatcanvas.utilities.GUI.py lines 123-138