MosaicMainWindow.h: 2012-06-18 Steven Lambright - m_lastOpenedFile was being...

MosaicMainWindow.h: 2012-06-18 Steven Lambright - m_lastOpenedFile was being overly aggresively when remembering paths from previously opened files - it followed the cube paths inside of file lists. This is now corrected so that it'll remember the path to the file list instead of the path to the files in the file list. Fixes #848. 

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@4493 41f8697f-d340-4b68-9986-7bafba869bb8