US hierarchy generation simplification
US hierarchy generation simplification

- USLevelInclusionHierarchy is not needed.
- USLevelHierarchyWeights renamed to USHierarchyChildParent...
- ... and it outputs a table with only one parent per child,
  the one with highest weight.

CartoDB/bigmetadata,CartoDB/bigmetadata,CartoDB/bigmetadata,CartoDB/bigmetadata