Removed existential bound
Merge branch 'experiment/arities/containers' into feature/static-queries
Fixed flatten eval test
Great namespace refactoring
Removed relations
Symplifying names (Any- is ommited here):
- ElementType -> GraphElement
- EdgeType -> Edge
- VertexType -> Vertex
- ContainerType -> NestedGraphType (#Of -> #Inside)
- synonims for container object types: type ExactlyOne = ExactlyOne.type
- unifying its constructors: apply() -> of()
- Combinator -> PathCombinator
Changed edge constructor to use fancy syntax
Fixed containers multiplication; added test
Last minor fixes
Merge branch 'refactoring/better-namespaces' into feature/static-queries
Revert "WIP: making in/out first order members (and deriving inC/int/outC/outT)"

This reverts commit 6b876d07984cd53fae1640f03aa834ccd3647e9d.
Merge branch 'feature/static-queries' into experiment/arities/simpler-in-out
WIP: trying approach with recursive graph-types