Changes the dust policy to require transactions to add the dust
limit itself rather than the relay or wallet fee to the fees paid
when creating dust outputs.
This both disincentivizes dust outputs the same as before when dust
and minumum fee were equal and greatly simplifies the rule, as it
no longer requires 2 variables to calculate dust, but just one:
"If an output is under x, add x to the fee."
Prepares for having more than one dust limit configured, yet
allowing the same function to return whether or not an output is
dust.
Implements the check with nDustLimit (-dustlimit) for relay related
queries, and - for lack of alternatives - uses the same parameter
for CWallet::GetRequiredFee until a wallet-specific dust limit is
introduced
* Change from a block target number to using speed labels which pick predefined fee values.
* Remove smart fee labels from send coins control dialog.
* Rename slider position configuration for Qt, as smart fee slider settings are not compatible with preset fee settings.
