Myokit

- Added more import/export options to the IDE menu.
- Updated `component.code()` to always outout aliases in the same order.
- Added method to find Markov models in a Myokit model.
- Added method to convert Markov models to compact form.
- Added method to convert Markov models to full ODE form.
- LinearModel now converts to full ODE form.
- Added method `lib.guess.membrane_capacitance`.
- Added method `lib.guess.membrane_currents`.
- Added (experimental) EasyML export.
- Small bugfixes and documentation updates.
- Improved exception handling when evaluating a unit containing an invalid power.
- Made default script and protocol robust against incompatible units.
- Made CellML API `from_myokit_model` more robust against invalid units.

- Rewrote CellML import and export, with improved error handling and validation.
- CellML import now converts hardcoded stimulus equation to Myokit protocol.
- CellML export now converts Myokit protocol to hardcoded stimulus equation.
- CellML import now generates more approprate default scripts.
- CellML import now supports unit conversion between components.
- CellML export now infers units from RHS if no unit set.
- CellML import and export can now both handle Web Lab `oxmeta` annotations.
- Various changes and improvements to MathML parsing.
- Added missing `__iter__` to Model and VarOwner.
- The myokit.Name expression can now wrap objects other than myokit.Variable, allowing Myokit's expression system to be re-used for non-myokit expressions.
- Removed myokit.UnsupportedFunction.

- Added guessing module, with method to guess which variables (if any) represent the membrane potential and stimulus current.
- Fix for sundials development versions.
- Fixes for PySide2 support.

- Myokit is now released under a BSD 3-clause license
- Bugfix to `myokit step` command line tool.

- Added PySide2 support.
- Deprecated PyQt4 and PySide.
- Added a method `Model.remove_derivative_references()`.
- Bugfix to `Model.repr()` for models with no name.
- Added `Model.timex()`, `labelx()` and `bindingx()`, which work like `time()`, `label()` and `binding()` but raise an exception if no appropriate variable is found.
- Deprecated `lib.multi.time()`, `label()`, and `binding()`.

- Added method `Variable.convert_unit()` that changes a variable's units and updates the model equations accordingly.
- `Unit.conversion_factor` now returns a `Quantity` instead of a float, and accepts helper `Quantity` objects for incompatible conversions.
- Added `Unit.clarify()` method that gives clear representation.
- Added `Unit.multiplier_log_10()` method.
- Added `rtruediv` and `pow` operators to `Quantity` class.
- Small bugfixes to `myokit.lib.hh`.
- Stopped requiring HH alphas/betas and taus/infs to depend on V (allows drug-binding work).
- Bugfix: Time variable in CellML export no longer has equation or initial value.
- CellML export: components now ordered alphabetically.
- Variables with an `oxmeta: time` meta annotation are now exported to CellML with an oxmeta RDF annotation.
- CellML import now allows `deca` prefix.
- Added CellML identifier checks to cellml import.
- Renamed `DataLog.find()` to `find_after()`.
- Added DataLog.interpolate_at(name, time) method.
- Improved colormap used in `plots.cumulative_current()`.
- Bugfix to 'myokit step' for models without a name meta property.
- Updated sign error handling in `myokit.step()`.
- Added IDE shortcuts for unit checking.
- IDE now jumps to unit errors, if found.
- Improved exception display in IDE.
- Var_info now includes unit.
- Fixed bug in `Unit.__repr__` for small multipliers.
- Improved notation of units when complaining about them.