Refactored the location of the progress_callback so that the UI can
specify it and ensure it is used by the automagics process as well as
the plugins themselves.
The progress_callback function has also had an optional description parameter
added, so that it can differentiated in case two scans happen
simultaneously.
So this is where I ripped out the guts of the dependency tree
and made it a little better defined in some ways, and delayed
populating it in others. The validate function signature has
changed and I'm still up in the air whether to validate with
True/False or throw/catch exceptions.
So now, configurables have a list of requirements, these are
then bundled into a single requirement and can be passed to
automagic. Automagic runs a set of things over the deptree
to help build/manage it. These run in order of priority.
The tree is still built from the top down, but now automagic
can build branch from the bottom up and try and splice them
into the tree where appropriate. Hopefully this will make it
easier to see follow.
Mike Auty