Added a method for computing the residual of the system of ODEs.
Got rid of methods for comparing trajectories.
Improved name of the residual method.
Methods now in alphabetical order.
Fixed relative import syntax
Added a test of the compute_residual method.
Got rid of base class.
Got rid of extraneous code.
Fixed some small bugs in the compute_residual method.
Basic test case for compute_residual method.