Remove uneeded const

The const means nothing, because the pointer is being copied anyways. This also fixes this warning:

`ConnectionState.hpp:44:9: warning: 'const' type qualifier on return type has no effect [-Wignored-qualifiers]`

Author: russelltg

src/ConnectionState.hpp

@@ -41,7 +41,7 @@ class ConnectionState
 
   void setLastHoveredNode(Node* node);
 
-  Node* const
+  Node*
   lastHoveredNode() const
   { return _lastHoveredNode; }