7de1de7 Add new fee structure with all sub-fields denominated in BTC (mryandao)
Pull request description:
the denomination for `fee` is current in btc while the other such as `decendentFee` and `ancestorFee` are in satoshis.
Tree-SHA512: e428f6dca1d339f89ab73e38ce5903f5465c46b159069d9bcc3f8b1140fe6657fa49a11abe0088e9f7ba9999f64af72a349a4735bf5eaa61b8e4a185b23543f3
Backport of Core PR12240
https://github.com/bitcoin/bitcoin/pull/12240/
Also included PR13109 and PR13124 (small typo fixes)
https://github.com/bitcoin/bitcoin/pull/13109/
https://github.com/bitcoin/bitcoin/pull/13124/