testrpc server logs are leaking into stdout

* Populus Version: 2.2.0
* OS: osx

### What was wrong?

Expected output:
```
~/G/t/greeter % python deploy.py
Head block is 0 on the testrpc chain
Owner address is 0x82A978B3f5962A5b0957d9ee9eEf472EE55B42F1
Deploying Greeter.sol
Greeter address is 0xc305c901078781c232a2a521c2af7980f8385ee9
Hello
```

Actual Output:
```
~/G/t/greeter % python deploy.py
127.0.0.1 - - [22/Dec/2017 00:45:57] "POST / HTTP/1.1" 200 44
Head block is 0 on the testrpc chain
127.0.0.1 - - [22/Dec/2017 00:45:57] "POST / HTTP/1.1" 200 83
Owner address is 0x82A978B3f5962A5b0957d9ee9eEf472EE55B42F1
Deploying Greeter.sol
127.0.0.1 - - [22/Dec/2017 00:45:57] "POST / HTTP/1.1" 200 48
127.0.0.1 - - [22/Dec/2017 00:45:57] "POST / HTTP/1.1" 200 44
127.0.0.1 - - [22/Dec/2017 00:45:57] "POST / HTTP/1.1" 200 1350
127.0.0.1 - - [22/Dec/2017 00:45:57] "POST / HTTP/1.1" 200 107
127.0.0.1 - - [22/Dec/2017 00:45:57] "POST / HTTP/1.1" 200 391
127.0.0.1 - - [22/Dec/2017 00:45:57] "POST / HTTP/1.1" 200 2143
Greeter address is 0xc305c901078781c232a2a521c2af7980f8385ee9
127.0.0.1 - - [22/Dec/2017 00:45:57] "POST / HTTP/1.1" 200 235
Hello
```

Source:
```python
contract_name = 'Greeter'
chain_name = 'testrpc'

def deploy():
with Project().get_chain(chain_name) as chain:
print(f"Head block is {chain.web3.eth.blockNumber} on the {chain_name} chain")

owner = chain.web3.eth.coinbase
print('Owner address is', owner)

print(f'Deploying {contract_name}.sol')
instance = deploy_contract(chain, owner, contract_name)
print(f'{contract_name} address is', instance.address)

print(instance.call().greet())
```

#### Cute Animal Picture


Reproduce the issue by running the deploy.py example with the testrpc chain and compare the output with the expected and actual logs shown here. Trace how the testrpc server handles requests; done means the deployment output remains while the 127.0.0.1 request lines no longer leak into stdout.

Written by the indexing model from the issue text.