Rather than drop files temporarily into the master security lists
directory during unit tests, create temporary directories for the
tests. This avoids issues when the tests are being run at the same
time as other code that uses the real security lists data.
and added a new test case
was not iterating over lookup date directory names, and
therefore mising all by one list of stocks.
discovered because of differing sort orders between
my local machine, other devs, and travis ci.
jfkirk