Add 'get' function to retrieve valeus from global config.

Also rename 'configure' function to 'load'.
Add initial timeframe catalog and some more stub timeframes.
More plugin stubs and fixed syntax errors
Add 'get_int' function which returns config values as integer (if
possible).

At some point, the whole config mechanism will have to be rewritten,
this is not quite elegant. Maybe oslo.config from OpenStack can be
re-used.
Add 'init_from_config' method. Some PEP-8 cleanup
Use config.get_int rather than config.get for verbosity
Simplified timeframe configuration
Make use of recent config/plugin/timeframe improvements