Maboss

- Restore a cache of plotted figures
- Fix the figsize argument for 3D plotting
- Fix the state filtering
- Adding dtype for pandas Series (planned change in pandas default behaviour)

- Fixed ensemble simulation copy()
- set_models_path now also work with zipped ensembles
- legend can be deactivated on piecharts
- PCA model comparison also work on state distributions
- PCA methods now allow a matplotlib axes as parameter
- PCA methods allow a cutoff_arrows to hide small arrows.
- Added a 3D plotting method for model distributions

- Allowing per-model mutations
- Improvements in plotting
- Filters now also work with states
- Bugfixes

Two bugs in the parser that Gautier found :

- Refstate should allow -1 values (which ignores it)
- A node can have non-defined rates. In this case, default rates are used

Added a first version of the MaBoSS C library interface.
For classic simulation, and upmaboss simulations, setting cmaboss=True in the run() command will use the C library.

Also added a option to run through a optimized engine, which only returns the probability of the last states. For classic and upmaboss simulations, setting only_final_state=True in the run() command will use this new engine.