Allow adjustable limit on the minimum transaction value.

Accept only transactions for which all output values are above a minimum amount (dust limit). The mimimum defaults to zero (everything above zero is accepted).
Added Qt interface options pane called "Advanced" to set this value.
Allow blocking of specific destination addresses.

Transactions destined for these addresses will not be accepted by this node.
Added a field in the "Advanced" options pane to set the list of filtered addresses.