symfit 0.5.2

Symfit 0.5.2 offers a fantastic new feature: ODEModels now also accept parameter objects as initial values, allowing them to be optimized as well! Additionally it undoes some of the performance penalties that were accidentally introduced in 0.5.0-0.5.1, making it as fast again as the 0.4.x series.

Full changelog:

• ODEModels can now use parameters for their initial values, so these can be optimized during the fitting!
• Hessian and jacobian models are now generated lazily to prevent slow model building.
• The output of models was a namedtuple, which has a limit to the amount of arguments in older python versions. This has therefore been replaced by a custom tuple subclass called ModelOutput.
• Numerous small big fixes
• Documentation improvements