Add autocomplete to bitcoin-qt's console window.

Removed externs
Added listCommands() to CRPCTable

Move autocomplete init to RPCConsole::setClientModel()

src/rpc/server.h

@@ -145,6 +145,12 @@ public:
      */
     UniValue execute(const std::string &method, const UniValue &params) const;
 
+    /**
+    * Returns a list of registered commands
+    * @returns List of registered commands.
+    */
+    std::vector<std::string> listCommands() const;
+
 
     /**
      * Appends a CRPCCommand to the dispatch table.