Resolve "Add LQR Control to Simulink"

Feature Description

Implements an LQR Controller in the MATLAB/Simulink simulation

Implementation Details

Added the following features

• Symbolic linearization of non-linear model (linearization.m)
• Construction of LQR controller with diagonal weighting matrices (initial_lqr.m)
• Copy of modelParameters.m with Matt Rich's parameters for testing (`rich_params.m')
• Tools to run simulation, observe error, and optimize LQR weights (run_once.m, lqr_err.m, and repeated_opt.m)

Impacted Areas

• Controls