Refactor management of resources

[lewismorgan]

As of now, there is a hard dependency on a listing of resource and resource groups. It was done this way in order to accept data from GalaxyHarvester. In order to handle resource groups properly, HarvesterDroid should make use of a single ResourceTree class. Trackers will need to define how they construct their resource trees and convert it into a proper ResourceTree class. Using this method, it will be extremely easy to traverse down resource trees and get top level resources, as well as decouple a reliance on text files to be present.

In order to allow this there will need to be a new API class called Provider. Provider will be the new name for trackers. Providers should provide all data information that is needed by HD. Providers should never need to know when to download something — that’s for HD to figure out. The following are what providers will probably do given HarvesterDroids current functionality

• Downloading a single resource
• Downloading list of galaxies
• Downloading a resource tree: Different galaxies often have different trees!
• Store galaxy resource information?

[lewismorgan]

Initial state for trackers targeted for 2.0 because of #17 .