Implement italic font support.

st.info

@@ -83,15 +83,16 @@ st| simpleterm,
 	op=\E[39;49m,
 	pairs#64,
 	rc=\E8,
-	rs1=\Ec,
-	rs2=\E[4l\E>,
 	rev=\E[7m,
 	ri=\EM,
+	ritm=\E[23m,
 	rmacs=\E(B,
 	rmcup=\E[?1049l,
-	rmkx=\E>,
+#	rmkx=\E>,
 	rmso=\E[23m,
 	rmul=\E[m,
+	rs1=\Ec,
+	rs2=\E[4l\E>,
 	sc=\E7,
 	setab=\E[4%p1%dm,
 	setaf=\E[3%p1%dm,
@@ -99,9 +100,10 @@ st| simpleterm,
 	setf=\E[3%?%p1%{1}%=%t4%e%p1%{3}%=%t6%e%p1%{4}%=%t1%e%p1%{6}%=%t3%e%p1%d%;m,
 	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=\E(0,
 	smcup=\E[?1049h,
-	smkx=\E=,
+#	smkx=\E=,
 	smso=\E[3m,
 	smul=\E[4m,
 	tbc=\E[3g,