Banner added.
Changing a bit the way reports are produced.
Conditions related to DurationPersons now in better shape (and place).
A bit more of rationalizing and commenting in the code related to
DurationPersons class.
Including SCM, ITS in demographics report.
Rationalization of conditions, including them in a common hierarchy.
Ages analysis seems to work now with changes in grimoirelib_alch.
Timezone analysis now seems to work too, with the new structure
in grimoirelib_alch.
Almost complete restructure and code reuse in *_query.py and related
modules.
Analysis adapted to the new *_query.py interface.
Timezone analysis now uses timezones() method in scm_query_tz.py.