[PULL] add 'settxfee' RPC

[xf2_org]

URL: https://github.com/bitcoin/bitcoin/pull/150

Add 'settxfee' RPC, to change TX fee setting at runtime

This clamps TX fee, if not zero, between "network minimum" (0.01) and 5 BTC (IMO sanity limit).

Presumably, the "network minimum" might be lowered, as is occasionally discussed on IRC and forum. This RPC prevents setting TX fee below network minimum.

[Luke-Jr]

This introduces a regression, since -settxfee accepts <0.01 right now, and it's sane to do so.

[xf2_org]

This introduces a regression, since -settxfee accepts <0.01 right now, and it's sane to do so.

That's intentional, not a regression.

[j16sdiz]

Remove the    if (nAmount < CENT) and   if (nAmount > (5 * COIN))  check.
API should be as powerful as (if not more powerful then) command line.

[Luke-Jr]

This introduces a regression, since -settxfee accepts <0.01 right now, and it's sane to do so.

That's intentional, not a regression.

It's a regression by definition, because it works today and your patch breaks it.

[Gavin Andresen]

I can see the GUI not allowing a less-than-CENT to save fat-fingered users from themselves, but I think the RPC should allow it; at the very least it makes it possible for a kind of grass-roots movement to arise between miners and people generating transactions so if we start seeing a lot of transactions with less-than-CENT-per-kbyte-fees then that's a really good indication the default definition of "free" needs to change.

And now that the RPC and GUI allow full-precision amounts for send/move, there is no problem with "I got 50.000001 bitcoins from mining, how do I send ALL of them?"

[xf2_org]

Updated pull request, removing the ValidFee() check.