Added a “factory pattern” to DevFunds to allow for async calls to be made during object construction. This allows for `web3.eth.getAccounts` to be called and the `accounts` property assigned on instantiation.
This modification allows each unit test case to be run independently of the others.
Finished added unit tests for dev_funds. These are weak tests as the FakeIpcProvider does not provide enough support for keeping track of accounts and balances and instead we are injecting the provider responses in the tests, which kind of defeats the purposes of the tests. Instead, the FakeIpcProvider should be a little smarter and do more of what a real node would do.