Reverting smacs and rmacs to the xterm defaults.

These are needed by ncurses to correctly handle the switch between line
drawing. The changes to the alternative characterset code already fixed the
urwid hack.

st.info

@@ -159,7 +159,7 @@ st| simpleterm,
 	rev=\E[7m,
 	ri=\EM,
 	ritm=\E[23m,
-	rmacs=^O,
+	rmacs=\E(B,
 	rmcup=\E[?1049l,
 	rmir=\E[4l,
 	rmkx=\E[?1l\E>,
@@ -175,7 +175,7 @@ st| simpleterm,
 	sgr0=\E[0m,
 	sgr=%?%p9%t\E(0%e\E(B%;\E[0%?%p6%t;1%;%?%p2%t;4%;%?%p1%p3%|%t;7%;%?%p4%t;5%;%?%p7%t;8%;m,
 	sitm=\E[3m,
-	smacs=^N,
+	smacs=\E(0,
 	smcup=\E[?1049h,
 	smir=\E[4h,
 	smkx=\E[?1h\E=,