bdNode::processRemoteQuery() now handles get_hash request, and replies.

This is the link between 2a and 2b:
// #### get_hash message process
// [1] peer1.msgout_get_hash -> [2a] peer2.msgin_get_hash
// [2b] peer2.msgout_reply_hash -> [3] peer1.msgin_reply_hash
ocd on whitespace for bitdht_peers_reply_hash_msg
updated .gitignore for g++ gch files