corrected burntx nExpiryHeight to prevent duplication of importtx (malleability)
added importcoin validation for amount, ac_pubkey
added sourcetx creation with amount in opret
-ac_beam and -ac_coda cannot be active at the same time
Clusters can do import coin normally even with self-import chains.
-ac_import=KMD (any bitcoinprotocol coin) will make a side chain (not
implemented yet)
Theoretically -ac_beam or -ac_coda can work with side chain (not
implemented yet other than chain params)
