OPC tweak

Make extruded mesh construction slightly more verbose w.r.t specifying the gdim of the resultant mesh.  This allows us to have cylinder meshes.  Some cylinder tests are provided.

requires the following:
https://bitbucket.org/mapdes/ufl/pull-request/17/allow-outerproductcell-to-be-constructed/diff
https://bitbucket.org/mapdes/ffc/pull-request/54/add-new-cells-to-codesnippet-dicts/diff