Add option to just update lin_state without jacobian

[stevencarlislewalker]

This is an important ticket, because it is possible that the user does not specify a true disease free equilibrium and does not turn off all of the flows required to linearize when defining state construction on the C++ side. When this happens it is possible that the current R engine make_state will differ from the current TMB engine make_state (which uses true Jacobian calculation and assumes true linearization).

[stevencarlislewalker]

This will be a simple and entirely R side task with the new engine https://canmod.net/misc/cpp_side.html#parameters