v0.5.2

• Added new sweep and autosweep methods to Model
  • Added plot routines to the results of those routines to make it easy to plot a 1D sweep.
• Added new summary method to solution_array.
  • It and table accept iterables of vars, will only print vars in that iterable (or, by default, all vars)
• Cleaned up and documented the interactive submodule
  • removed contour and sensitivity plots
  • added a 1D-sweep plotting function
  • added that plotting function as an option within the control panel interface
• Overhauled and documented three types of variables whose value is determined by functions:
  • calculated constants
  • post-solve calculated variables
  • between-GP-solves calculated variables (for Sequential Geometric Programs)
• Fix Bounded and implement debug() for SPs
• Apply subinplace to substitutions dictionary as well
• Require GP substitutions to be Numbers only
• Extend Bounded to one-sided bounds
• Print model's numbers by default, unless "modelnums" in exclude
• Implement lazy keymapping, allowing GP/SP results to be KeyDicts
• Handle Signomial Inequalities that become Posynomial Inequalities after substitution
• Various documentation updates
• Various bug fixes