+ remove peers who do not meet the minimum score

* minor bug fixes and documentation improvements
* do not cleanup peers if we have no online peers (probably not
connected anyway)
* do not run peer cleanup until a min
* do not spam block list on shutdown during block sync
* use correct thread decrement in peerCleanup
* added trust int to address table, not used yet

onionr/core.py

@@ -200,7 +200,8 @@ class Core:
             powValue text,
             failure int,
             lastConnect int,
-            lastConnectAttempt int
+            lastConnectAttempt int,
+            trust int
             );
         ''')
         conn.commit()