Added and exposed wnoutrefresh, werase, winsch

wnoutrefresh seems like an important curses call for updating windows in a multi-window setup.  It certainly looks a lot better than just using wRefresh to me.

I needed winsch for being able to write the lower-right corner of the screen, as per several discussions online:

http://lists.gnu.org/archive/html/bug-ncurses/2007-09/msg00002.html