Merge pull request #2265 from RosettaCommons/roccomoretti/grid_global_fix
Fix global state usage in ScoringGrids
The protocols::qsar::scoring_grids::GridManager was a strange mix of a global cache and modifiable global state. That wasn't great because the implementation resulted in a lot of cross-dependencies between grid usage.
This pull request should hopefully decouple the global grid caching (still held by GridManager) from the modifiable state (now held in local variables as a GridSet object).
An upshot of this change is now you can have multiple GridSet objects in a single RosettaScripts run. Previously, all grids you were working with were . The multiple-grid approach is being done in a backwards-compatible way, so existing XMLs should be able to work as-is.