Change origins.graph.Nodes key-based access to be case-insensitive

This prevents needing to know ahead of time if the backend lowercases
the names of the nodes. One caveat to this is if the backend supports
case-sensitive names and in practice there are conflicts. If so, a
flag can be denoted on the client to toggle this behavior.
Remove arbitrary lowercasing of names in Oracle backend

This was done primarily to make the traversal layer easier to work with.
Now that the origins.graph.Nodes structure is case-insensitive, this is
not longer an issue.
Implement aggregation methods for database columns
Change hard-coded SQLite query parameters to be bound at runtime