Updated the search for treasury data when there is none for the
test end date.
It could be that the end date is not a trading day, or we could
just be missing treasury data. In either case, we try to recover
more gracefully now, by searching as far as possible and maybe
logging a warning.
Similarly, if there is no benchmark data for the test end date,
look for the next trading day. If we really have no data,
blow up with our own explicit exception, instead of overflowing
in our search for dates in the future.
By having run() use a capital_base member of the algorithm to
create the trading environment, the capital base should now be
configurable in the instantiation of the algorithm.
e.g.:
```
algo = LowCapitalBaseAlgorithm(capital_base=1000.0):
```
So that the zipline library can be used when installed to a
write-protected location, e.g. the global site-packages,
moving the download files to a directory in the user's path,
which should be writeable.
For now, choosing a ~/.zipline/data location.
Hopefully, this helps ease ramp up time for developing against
market data, without us distributing the data.
We do a check for the data when attempting to read the msgpack
files, if they don't exist the loader makes a web request and
retrieves and serializes the data for the user.
Provides a loader for:
- curves from data.treasury.gov
- benchmarks from Yahoo! Finance
Adds dependency of requests library in dev requirements.
Mostly whitespace, line width and other spacing changes.
Also, removes use of deprecated has_key in favor of `in`
Going forward new patches should pass running `flake8` before
submission.
Richard Frank