EBBO by checking all sumbitted solutions.

Historical Data Functionality EBBO Test  (#10)

First PR for EBBO Tool:

cow_endpoint_surplus.py can be run from test.py for historical data
testing by specifying start and end blocks or even checking EBBO for a
single hash, or from daemon_analytics.py for live monitoring where the
program wakes every 30 mins and runs the current EBBO test on
transactions in the period it was asleep.
configuration.py holds a logging function, and certain abstracted values
used in cow_endpoint_surplus.
directory.py is used to fetch an etherscan api key from a config.py file
in the root directory.