handle statusbar blanking in one place instead of many, so that it

handle statusbar blanking in one place instead of many, so that it
always works consistently, per Benno Schulenberg's patch (with a few
tweaks of mine); also, blank the statusbar after 26 keystrokes instead
of 25, for compatibility with Pico

git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@3541 35c25a1d-7b9e-4130-9fde-d3aeb78583b8