Previously you could have `override` set to True on parameters that
only existed in the current scope.
Now if you try to override a parameter that doesn't exist higher up
in the hiarchy you will get a ValueError.
Previously if parameters with the same names and override set to True
were added to an extension at the same level one would silently
override the other.
This is no longer the case and an error will be show instead.
Also added tests to check that this is handeled correctly
- standardisded on a single context argument
- removed Device.init() no longer necessary as initilize now
automatically gets propagated up the hierarchy. Renamed the existing
use of it to "initilize".
- related pylint cleanup.
- added initialze and finalize methods to workloads, which were the only
major extension types that did not have them
- Semanatics for initialize/finalize for *all* Extensions are changed so
that now they will always run at most once per run. They will not be
executed twice even if invoke via istances of different subclasses (if
those subclasses defined their own verions, then their versions will
be invoked once each, but the base version will only get invoked
once).
