Tensor algebra abstract type interoperability setup
improved dispatch
exported more syntax alias
enhanced TensorAlgebra type stability
improved operator aliasing
refined algebra dispatch
defined metric, antimetric, antidot, etc
implemented anti-product compatibility
exported new TensorGraded{V,G} aliases: Scalar, GradeVector, Bivector, Trivector
transferred countvalues, evenvalues
transferred extra field algebra definitions