'interested' commit 3/1/14

Removed ‘payload’ property as ‘interested’ messages have no payload.
Created functionality to add data to the log file.
Once a peer receives an interested message, it should send that piece
to the peer sending the message. Therefore, this method should notify
the receiving peer to sendPiece(pieceIndex).  (This method can be
better executed once functionality for sending pieces exists).
"not interested' commit 3/1/14

Removed ‘payload’ property as ‘not interested’ message types have no
payload.
Added functionality to add information to log file when a peer receives
a ‘not interested’ message.