Get rid of empty line at bottom of output frame. (Reported by DigitalMan)

Put new messages at actual bottom of frame, not just visible area when scrolling, but don't scroll down if in scrollback mode.
Re-fix problem with non-string values from inputline.

xtrn/mrc/mrc-client.js

@@ -13,6 +13,8 @@ load('scrollbar.js');
 load('inputline.js');
 load(js.startup_dir + 'mrc-session.js');
 
+var input_state = 'chat';
+
 var f = new File(js.startup_dir + 'mrc-client.ini');
 f.open('r');
 const settings = {
@@ -114,13 +116,26 @@ function init_display() {
     return f;
 }
 
+function append_message(frames, msg) {
+    const top = frames.output.offset.y;
+    if (frames.output.data_height > frames.output.height) {
+        while (frames.output.down()) {
+            yield();
+        }
+        frames.output.gotoxy(1, frames.output.height);
+    }
+    frames.output.putmsg(msg + '\r\n');
+    frames.output.scroll(0, -1);
+    if (input_state == 'scroll') frames.output.scrollTo(0, top);
+}
+
 function display_message(frames, msg, colour) {
-    const body = pipe_to_ctrl_a(msg.body || '').split(' ');
-    frames.output.putmsg(body[0] + '\1n\1w: ' + body.slice(1).join(' ') + '\1n\1w\r\n');
+    const body = pipe_to_ctrl_a(truncsp(msg.body) || '').split(' ');
+    append_message(frames, body[0] + '\1n\1w: ' + body.slice(1).join(' ') + '\1n\1w');
 }
 
 function display_server_message(frames, msg) {
-    frames.output.putmsg('\1h\1w' + pipe_to_ctrl_a(msg || '') + '\r\n');
+    append_message(frames, '\1h\1w' + pipe_to_ctrl_a(truncsp(msg) || ''));
 }
 
 function display_title(frames, room, title) {
@@ -148,7 +163,6 @@ function new_alias() {
 function main() {
 
     var msg;
-    var input_state = 'chat';
     var break_loop = false;
     const nick_colours = {};
 
@@ -228,7 +242,7 @@ function main() {
     while (!js.terminated && !break_loop) {
         session.cycle();
         user_input = inputline.getkey();
-        if (typeof user_input != 'undefined') {
+        if (typeof user_input == 'string') {
             if (input_state == 'chat') {
                 if (user_input.substring(0, 1) == '/') { // It's a command
                     cmd = user_input.split(' ');