Convert tuple to list in getUsableTxOutList()

I get this error when trying to send a transaction:

    (ERROR) Traceback (most recent call last):
      File "/home/kalakris/bitcoin/BitcoinArmory/qtdialogs.py", line 5133, in createTxAndBroadcast
        txdp = self.validateInputsGetTxDP()
      File "/home/kalakris/bitcoin/BitcoinArmory/qtdialogs.py", line 5312, in validateInputsGetTxDP
        utxoSelect = PySelectCoins(utxoList, totalSend, fee)
      File "/home/kalakris/bitcoin/BitcoinArmory/armoryengine.py", line 5388, in PySelectCoins
        utxos = PySortCoins(unspentTxOutInfo, method)
      File "/home/kalakris/bitcoin/BitcoinArmory/armoryengine.py", line 4980, in PySortCoins
        random.shuffle(utxosNoZC)
      File "/usr/lib/python2.7/random.py", line 288, in shuffle
        x[i], x[j] = x[j], x[i]
    TypeError: 'tuple' object does not support item assignment

It seems like utxosNoZC should be a list and not a tuple. The attached patch fixes this issue. (May also fix issue #24).