Improve performance in userinfo

* Implement a nick -> user mapping, preventing a superfluous SSCAN on
the entire dataset for when networks are disconnected
* Use one thread for all channels when a network instance is
disconnected, instead of one thread per channel
* Made returns comprising of only a list into tuples

utils/parsing.py

@@ -0,0 +1,15 @@
+def parsen(user):
+    step = user.split("!")
+    nick = step[0]
+    if len(step) == 2:
+        step2 = step[1].split("@")
+        if len(step2) == 2:
+            ident, host = step2
+        else:
+            ident = nick
+            host = nick
+    else:
+        ident = nick
+        host = nick
+
+    return (nick, ident, host)