The source project of this merge request has been removed.
Feature/strain product lambda rework
This makes the StVenantKirchhoff and *ViscosityAssembler use lambdas to compute the stress from strain. I'd eventually like to make the NormalStressBoundaryAssembler accept a lambda, too (e.g. to allow for heterogeneous viscoelasticity rather than homogeneous elasticity).
Maybe the VariableCoefficientViscosityAssembler can disappear again completely now. Pretty sure I'm the only who uses it anyway.
Thoughts? Opinions? I don't currently consider this a great improvement so I'm open for anything, including outright rejection.