Bump to v0.0.21

Better retry + option to set up request options

Added retry support (5 retries)

Bump to v0.0.18

Bump to v0.0.17

Added support for SmartTrades V2

BUGFIX: Fix issue with signature is invalid + other improvements from @…

…eladeon (thanks for that).

Small typo fix

Bump to version 0.0.13

bump to version 0.0.12