Create MATLABOptions plugin

Added an OptionsPlugin for controlling MATLAB configuration.
Refactor MCL Utils to use MATLABOptions

MATLABOptions exposes configuration preferences for how MATLAB should be
launched. To take advantage of these, we needed to update how
MATLABControlUtils is being used:

* MATLABControlUtils is now functional, accepting various parameters (or
  just a MATLABOptions directly) and using these to construct a
  MatlabProxy as appropriate.
* MATLABBindings and ScriptEngine now need access to a Context, to get
  the OptionsService and MATLABOptions to use in constructing proxies.