Overhaul of function to optimize connection matrix parameter

New version of shc_lv_params(). Takes different inputs.  Notably, only one time period is specified now, the global mean passage time, Tau. The saddle number, Nu, is also an input so that stability can be adjusted. Outputs either 3 or 4 parameter forms for Rho, the connection matrix, that can be used by shc_lv_create(). The function is slower as it uses toolbox functions directly as opposed to stripped down custom implementations. Eta renamed to Epsilon. D renamed to Delta.

Small fixes in shc_lv_transitiontime() and shc_lv_passagetime().

Signed-off-by: Andrew D. Horchler <adh9@case.edu>