added handling for ^A, ^E and left/right arrows in entry boxes.

Reference: /n/sources/patch/applied/libcontrol-entry-cursor-fix
Date: Wed Dec  5 00:50:43 CET 2007
Signed-off-by: bichued@gmail.com

--- /sys/src/libcontrol/entry.c	Wed Dec  5 00:38:41 2007
+++ /sys/src/libcontrol/entry.c	Wed Dec  5 00:38:35 2007
@@ -286,6 +286,20 @@
 			e->ntext--;
 		}
 		break;
+	case Kright:
+		if(e->cursor < e->ntext)
+			e->cursor++;
+		break;
+	case Kleft:
+		if(e->cursor > 0)
+			e->cursor--;
+		break;
+	case 0x01:	/* control A: beginning of line */
+		e->cursor = 0;
+		break;
+	case 0x05:	/* control E: end of line */
+		e->cursor = e->ntext;
+		break;
 	case 0x15:	/* control U: kill line */
 		e->cursor = 0;
 		e->ntext = 0;