remove FileFrame#getMainFrame method, and move the commonality from EditorFrame and ViewerFrame to FileFrame

git-svn-id: https://svn.mucommander.com/mucommander/trunk@3973 550a0b29-e8ba-4216-b148-48df7e53fc2c
change the minimum size of file viewer frame to be the same as the minimum size of file editor frame

git-svn-id: https://svn.mucommander.com/mucommander/trunk@3974 550a0b29-e8ba-4216-b148-48df7e53fc2c
fix for not using the system's line separator when saving a file that had no line separator when it was opened (ticket #438)

git-svn-id: https://svn.mucommander.com/mucommander/trunk@3975 550a0b29-e8ba-4216-b148-48df7e53fc2c
add comment that explains the last committed change

git-svn-id: https://svn.mucommander.com/mucommander/trunk@3976 550a0b29-e8ba-4216-b148-48df7e53fc2c
restoring the line wrap and line numbers settings of text viewer/editor from the previously used one
those settings are now saved in the snapshot file instead of the preferences file

git-svn-id: https://svn.mucommander.com/mucommander/trunk@3977 550a0b29-e8ba-4216-b148-48df7e53fc2c
Merge branch 'svn-sync'