* Create the FeeSettings object in genesis ledger.
* Initialize with default values from the config. Removes the need to
pass a Config down into the Ledger initialization functions, including
setup().
* Drop the undocumented fee config settings in favor of the [voting]
section.
* Fix#3734.
* If you previously used fee_account_reserve and/or fee_owner_reserve,
you should change to using the [voting] section instead. Example:
```
[voting]
account_reserve=10000000
owner_reserve=2000000
```
* Because old Mainnet ledgers (prior to 562177 - yes, I looked it up)
don't have FeeSettings, some of the other ctors will default them to
the config values before setup() tries to load the object.
* Update default Config fee values to match Mainnet.
* Fix unit tests:
* Updated fees: Some tests are converted to use computed values of fee
object, but the default Env config was also updated to fix the rest.
* Unit tests that check the structure of the ledger have updated
hashes and counts.
* Introduces amendment `XRPFees`
* Convert fee voting and protocol messages to use XRPAmounts
* Includes Validations, Change transactions, the "Fees" ledger object,
and subscription messages
* Improve handling of 0 drop reference fee with TxQ. For use with networks that do not want to require fees
* Note that fee escalation logic is still in place, which may cause the
open ledger fee to rise if the network is busy. 0 drop transactions
will still queue, and fee escalation can be effectively disabled by
modifying the configuration on all nodes
* Change default network reserves to match Mainnet
* Name the new SFields *Drops (not *XRP)
* Reserve SField IDs for Hooks
* Clarify comments explaining the ttFEE transaction field validation
Remove the implicit conversion from int64 to XRPAmount. The motivation for this
was noticing that many calls to `to_string` with an integer parameter type were
calling the wrong `to_string` function. Since the calls were not prefixed with
`std::`, and there is no ADL to call `std::to_string`, this was converting the
int to an `XRPAmount` and calling `to_string(XRPAmount)`.
Since `to_string(XRPAmount)` did the same thing as `to_string(int)` this error
went undetected.
Avoid custom overflow code; simply use 128-bit math to
maintain precision and return a saturated 64-bit value
as the final result.
Disallow use of negative values in the `fee_mult_max`
and `fee_div_max` fields. This change could potentially
cause submissions with negative values that would have
previously succeeded to now fail.
