Fix conflicting bitcoin counterparty conflict merge

Bitcoin reduced the tx return data bytes by half effectively cutting off
counterparty compatibility with 0.9.x see:
http://www.coindesk.com/developers-battle-bitcoin-block-chain/

This is to revert the bitcoin change so that we may one day support
counterparty, blockchain services and smart contracts

src/script.h

@@ -23,7 +23,7 @@ class CKeyStore;
 class CTransaction;
 
 static const unsigned int MAX_SCRIPT_ELEMENT_SIZE = 520; // bytes
-static const unsigned int MAX_OP_RETURN_RELAY = 40;      // bytes
+static const unsigned int MAX_OP_RETURN_RELAY = 80;      // bytes
 
 /** Signature hash types/flags */
 enum