Initial sdk-go release!

We're renaming the package from zeroex-go into sdk-go as it begins to include not only 0x wrappers, but also wrappers and utilities for our own Futures smart contract infrastructure, own TEC utils and it will be expanded further to include shared pieces to work with Injective Sidechain.

v1.8.9

avoid naming collision 1.8.9

v1.8.8

update to multiple base currencies 1.8.8

v1.8.7

v1.8.7

v1.8.4

v1.8.4

v1.8.1

Update futures.go

v1.8.0

updated futures.go wrappers