Import deprecate from log
join_domains: Use coordinates if we found them

When joining domains, only build a Domain without coordinates if we
didn't find any.
Implement OuterProductCell
Implement OuterProductElement
Implement OuterProductVectorElement

This is necessary if we want to build VectorFunctionSpaces on
OuterProductCells.
Implemented HDiv, HCurl
Do OPE degree using tuples (avoid quadrature bug); add docstrings
Added extruded facets to UFL
add cell2dim function for OuterProductCell (else passes to cellname2dim)
Rework OPE signature data for Domain change
Add reconstruct methods to OPE and friends

Necessary to rebuild with domain arguments.
Add domain to repr of OuterProductElement
Pass domain when building sub element in OPVE
Fix format string for OPVE
Indexed shouldn't override __getnewargs__
Update contributors list.