torcontrol improvements and fixes

- Force AUTHCOOKIE size to be 32 bytes: This provides protection against
  an attack where a process pretends to be Tor and uses the cookie
  authentication method to nab arbitrary files such as the
  wallet
- torcontrol logging
- fix cookie auth
- add HASHEDPASSWORD auth, fix fd leak when fwrite() fails
- better error reporting when cookie file is not ok
- better init/shutdown flow
- stop advertizing service when disconnected from tor control port
- COOKIE->SAFECOOKIE auth

src/net.cpp

@@ -263,6 +263,14 @@ bool AddLocal(const CNetAddr &addr, int nScore)
     return AddLocal(CService(addr, GetListenPort()), nScore);
 }
 
+bool RemoveLocal(const CService& addr)
+{
+    LOCK(cs_mapLocalHost);
+    LogPrintf("RemoveLocal(%s)\n", addr.ToString());
+    mapLocalHost.erase(addr);
+    return true;
+}
+
 /** Make a particular network entirely off-limits (no automatic connects to it) */
 void SetLimited(enum Network net, bool fLimited)
 {