Fixed error check for reserved variable names to prevent hard to debug failures.
Add new 2D quadrotor example, will make more complete in future. Added message IDs to error messages. Removed uneeded clutter.
Fixed error in checkVariables method. Added ability to add variables after constraints and objectives have been defined by adjusting sparse gradient sizes.
Adding capability for vector parameters and fixing bugs found while implementing. Started adding unit tests so I can better test when I break something.