put all configuration into a subdirectory
do not pass default config files

oslo.cfg does this work for use, therefore it is not needed to pass a
default config files list to the CONF object.
do not fail if we receive a datetime.datetime object

If somebody is not using an extract_from option, the upper manager will
try to read and parse the lastrun file, and we are going to get a
datetime.datetime object, that cannot be parsed by dateutil.parser. This
is a quick patch so that we do not fail, but this need to be refactored
though.
first set of unit tests
Fixed build, removed oslosphinx.
Changed README.rst to README.md
Changed format of README to md.

Updated README.
Basic intro to caso.
Removed readme.rst