Fix for improper wire connections to BC pipes

Added a check to make sure that neighboring blocks are actually currently redstone-connectable, as some mod blocks change this at runtime.  This specifically addresses red allow wires erronously connecting to BC pipes when there is not a Gate attached to the pipe.
Merge pull request #35 from Lycaonj/master

Fix for improper wire connections to BC pipes
- couldn't have done it better myself...