Revert "Add a tube mesh generation"

This reverts commit c1dafe3009406aaace208f186016cfd388c3c491.
Re-add cayley transform methods from other branch

Might be able to get them working now we have reduced integration.

Not working at the moment.
Some simplifications in residual code
Modify ArrayInterpolator to allow re-initialisation

(and use in residual calculations etc.)