Treat ElasticMembrane<HookesLaw> as incompressible
Treat ElasticMembrane<HookesLaw> as incompressible

Also added comments to remind that the bool is setting is_compressible
in the ElasticMembrane/ElasticCable constructors.

nicholasmalaya/grins,cahaynes/grins,vikramvgarg/grins,nicholasmalaya/grins,cahaynes/grins,nicholasmalaya/grins,vikramvgarg/grins,cahaynes/grins,vikramvgarg/grins,cahaynes/grins,cahaynes/grins,nicholasmalaya/grins,vikramvgarg/grins,vikramvgarg/grins,cahaynes/grins,vikramvgarg/grins