Fixed OSX preferences window; organized imports

wxPython/Cocoa does not support wx.CB_SORT, which caused the preferences
window to not open. This was fixed by sorting the entries in the
combobox without using CB_SORT.

See https://stackoverflow.com/questions/36139 for an explanation for the
solution to sorting based on the current locale.
Changed shebang to use python2 instead of python

It specifies the version of python, which allows it to work on Arch
Linux, which defaults to python3. Other distros may also default to
python3 in the future. I just forgot to use python2 when I changed
the shebang to use /usr/bin/env.