Gpkit

- variable and sensitivity breakdowns added
- in solution tables, models no longer default to being sorted by sensitivity

- no longer supports Python 2
- no longer supports mosek8 C bindings (the "mosek" solver)
- new dependencies: plotly, adce, numpy >= 1.16.4, matplotlib
- CVXOPT solver interface now uses linear programming formulations as applicable
- unicode printing by default, except on windows
- vastly improved diffing, pickling
- option for compressed solution pickles
- various speed improvements, especially during SGP solves
- reduced memory usage
- SGP solves now use the PCCP method
- raise warning on nonconvergence
- clearer solver errors
- new visualizations and improved old ones
- Sankey, Variable Reference, Treemap, Icicle plots

- The decorator `parse_variables(__doc__, globals())` replacing `exec parse_variables(...)`
- Support for the MOSEK9 exponential cone solver. [Install with pip!](https://docs.mosek.com/9.1/pythonapi/install-interface.html)

And some things that are best seen [in the docs](https://gpkit.readthedocs.io/en/latest/modelbuilding.html#multipoint-analysis-modeling):
- New and improved printing.
- v0.9.1: `A >= 2*s_(0,)*s_(1,) + 2*s_(0,)*s_(2,) + 2*s_(1,)*s_(2,), V <= s_(0,)*s_(1,)*s_(2,)`
- v0.9.9: `A >= 2*(s[0]*s[1] + s[1]*s[2] + s[2]*s[0]), V <= s[:].prod()`
- New syntax for modelnames.
- v0.9.1: `E_PowerSystem/Battery`
- v0.9.9: `PowerSystem.Battery.E`
- Dictionary constraints (which print nicely in addition to allowing easier access)
- {"definition of Re": Re == rho*V*c/mu, "definition of D": D >= 0.5*rho*V**2*CD*S}

* almost complete Python 3 support (except for `parse_variables`)
* Speedups, especially for SP solves
* Models now number themselves only if their whole path is copied by another Model
* Fixes to some sensitivity edge cases
* Dropped 400 lines of code (down to 5100) while adding 120 lines of tests (up to 2450). Still at 290 lines of examples.

* Much cruft removal, various speedups and fixes
* Auto-differentiation of linked sensitivities
* Simpler installation process
* Solution differencing and pickling
* Tight/Loose warnings in solution and in solution tables
* Tight/loose constraints in solution tables

- Variable's values are now used only in their first ConstraintSet; in other ConstraintSets they're free variables
- this can be overriden by setting `constant=True` during variable declaration
- MOSEK home directory can be set by a `MSKHOME` environment variable at build time
- `sol(var)` now always returns Pint Quantities, even if the variable is dimensionless
- `sol[...][var]`, on the other hand, now always returns floats / numpy arrays of floats
- Optional boundedness checking in docstring (see usage in [docs](http://gpkit.readthedocs.io/en/latest/modelbuilding.html#multipoint-analysis-modeling))
- Automatic boundedness checking for GPs
- [Sankey diagrams](http://gpkit.readthedocs.io/en/latest/visint.html)
- Many other fixes