RLG-Web client: initialize and restore the terminal when watching.

Since watchers might not get the curses initialization and ending
sequences, the terminal emulator needs to be set up for and restored
after watching.

rlgterm.js

@@ -581,6 +581,8 @@ function startwatching(gamenumber) {
       session.id = reply.id;
       session.playing = false;
       termemu.resize(reply.h, reply.w);
+      termemu.reset();
+      termemu.toAltBuf();
       setTitle("Watching");
       debug(1, "Watching with id " + session.id);
       setmode("play");
@@ -644,6 +646,7 @@ function gameover() {
   session.playing = false;
   ajaxstate.clear();
   setTitle("Game over.");
+  termemu.toNormBuf();
   nsend = 0;
   nrecv = 0;
   msgQ = [];