Corneto

- Fix minor bugs on the plotting system
- Add support for negative penalties
- Validation of signaling/metabolism modelling

- Major performance improvements for the ILP compilation
- Faster reaction network class

- Improved auto detection of solvers and backends
- Fixed bugs

Remove mandatory dependencies with cvxpy

- Bugfix when adding a reaction to an empty network
- Remove cylp dep. as mandatory so it can be installed on Apple M1 (cbc binaries not available)