Feature Request: Tx History Exports

[JSKitty]

Primarily, the most important use of this feature would be for Tax accounting reasons - it is currently impossible to export Tx history from MPW, which makes MPW very difficult to use for accounting purposes, unlike PIVX Core, which allows CSV exports usable for certain tax softwares like Koinly, etc.

Ideally, we should start off with a format similar to PIVX Core (for compatibility), and in the future, add support for additional formats which are better suited towards tax/accounting softwares like Koinly, CoinTracking, and more.

CSV is the common universal format, thus is the only one we should care about implementing.