[Teton Finance] v4 support

[alexkroeger]

This PR updates 0x-starter-project to v4.

Scenarios included:

• Fill a 0x API swap/quote response
• Fill ERC20 limit order
• Cancel pair limit orders
• Fill ERC20 RFQ order
• Fill ERC20 RFQ order with a maker order signer
• Subscribe to RFQ order fill events
• Execute Metatransaction
• Fill ERC20 OTC order
• Fill taker-signed ERC20 OTC order
• Fill a quote via TransformERC20

This work was funded by a 0x Community DAO grant to Teton Finance.

[SHA-2048]

Great work @alexkroeger , I've read all the scenario and code is very clear and readable.

I was wondering about use in a webApp use case, would there be anything specific to pay attention to? (I remember something about the provider where you need to define a special one for wrapping metamask)

Also most Dapp developers will be using the 0x API, so it can be very helpful to have a scenario for that as well

[alexkroeger]

Great work @alexkroeger , I've read all the scenario and code is very clear and readable.

I was wondering about use in a webApp use case, would there be anything specific to pay attention to? (I remember something about the provider where you need to define a special one for wrapping metamask)

Also most Dapp developers will be using the 0x API, so it can be very helpful to have a scenario for that as well

Hey @SHA-2048, thanks for reading thru!

Re: webapp use cases there is additional documentation on 0x-subproviders that I can link the readme.

Having 0x API scenarios would be useful--I'll look into that this week.

[jlin27]

Can we add the "Fill a 0x API swap/quote response" to this list?