Myokit

- Various improvements and bugfixes.

- Made `engine.realtime` contain the elapsed system time, not the absolute system time.
- Made `SimulationLog` suitable for multi-dimensional data.
- Added `StrandSimulation` object.
- Added Graph Data Extractor.
- Added `RhsBenchmarker`.
- Began work on CUDA export.
- Added Coffman-Graham algorithm for directed acyclic graph layer assignment.
- Added `get_last_number_of_evaluations()` method to `Simulation`.
- Various updates to the documentation.
- Various small bugfixes.

- Added export to strand/fiber simulation in Ansi-C.
- Added syntax for binding to external values.
- Various small bugfixes.

- Added plotting methods.
- Added benchmarking to simulation.
- Various improvements and bugfixes.

- Refactored `myokit.lib`.
- Added APD calculating function.
- Added APD measurement to simulation using CVode's root finding.
- Added padding function to `save_csv`.
- Created `SimulationLog` class.
- Various small bugfixes.

- Refactored import/export modules.
- Updated documentation.
- Added method to interpolate logged results.
- Improved performance in CVODE simulations.
- Added periodic logging option to simulation.
- Improved Explorer GUI.
- Added method to run euler/rk4 simulations.
- Added OrderedPiecewise class.
- Added progress bar to gui.
- Various small bugfixes.