Huge refactor to have everything working with socket.io

It fixes lots of bugs, can fallback to long polling, resize viewport of
terminals and share clients state of the session, so they all see the
same thing.

www/assets/style.css

@@ -1,3 +1,20 @@
 .selected button {
 	background-color: rgba(158,158,158,0.2);
 }
+
+md-card-content.terminal {
+    background-color: rgb(113, 113, 113);
+    padding: 0;
+}
+
+.terminal {
+    background-color: rgb(113, 113, 113);
+}
+
+.terminal .xterm-viewport {
+    background-color: rgb(113, 113, 113);
+}
+
+.terminal .xterm-rows {
+    background-color: #000;
+}