exchange rate bug fix
display locktime for transaction

display locktime for transactions if it is greater than 0.  Majority of
transactions will not display any value because default is 0.
BitcoinVenezeula Rates

Rates are taken from CoinDesk, modified for the true blackmarket rates,
not the "government approved" rates.
Merge pull request #607 from wozz/keyerror

exchange rate bug fix
Merge pull request #608 from wozz/locktime

display locktime for transaction
Merge pull request #609 from wozz/bitven

BitcoinVenezeula Rates
Merge branch 'master' of github.com:spesmilo/electrum into clean