Enabled show whitespace mode
Added windmove bindings, to switch windows using arrows

Use M-<arrow> to change window in XEmacs, instead of ``C-x o``.
Added (commented) bindings for ``C-c <arrow>`` too, since emacs
without X doesn't seem to handle M-<arrow>  correctly...
Added C-c <arrow> keybindings too for windmove in terminal mode