adding a bunch of changes for the new settings tab, but turning the lon/lat stuff back off for now; tweaked the validator for the numbers in the gui so it will allow None; cleaned up bugs in the 1D figure plotting code; added filters to reverse 2D data horizontally or vertically; more cleanup from moving constant values away to a separate module

git-svn-id: https://svn.ssec.wisc.edu/repos/glance/trunk@191 8a9318a1-56ba-4d59-b755-99d26321be01