In qmos, added the 'Auto Grid' functionality, an options dialog, the option to...

In qmos, added the 'Auto Grid' functionality, an options dialog, the option to select the source of the latitude and longitude extents, and an 'Auto Apply' option to update the grid as parameters are changed to the grid tool. Also changed the draw and clear grid buttons to a single 'Show Grid' check button. Updated the documentation to include these changes. Fixes #604.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@4601 41f8697f-d340-4b68-9986-7bafba869bb8