Noise now scaled internally by Beta in SHC passage time functions

Noise magnitude is now scaled by Beta to match Delta. Noise index shifting was also fixed.

Signed-off-by: Andrew D. Horchler <adh9@case.edu>
Significant improvements to parameter finding function shc_lv_params

Code was cleaned up. Non-uniform case again uses the much simpler FSOLVE instead of FMINCON. The residuals seem to be going to zero for this case now - possibly do to other functions and bugs being fixed. Also, noise and neighborhood size are scaled by Beta and and non-uniform solutions are now found for Beta = 1 too. Thanks Kendrick!

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