Release notes for cobrapy 0.6.2

Fixes

Fix in the ordering and rounding of FVA summary #525
Shared memory, improve speed during sampling #521
Debug model.remove_reactions to properly work with context manager. This lead to the deprecation of reaction.delete as this was not compatible with the concept of being able to later revert the change. #506, #508.
Adding two models (modela + modelb) again results in a model with the objective set to the sum of the two models objectives #505.
When adding reactions to a model, the reactions with identifiers identical to those in the model are ignored. #511

New features

model.merge can be used to merge two models, more flexibly than the overloaded + and += operators.

Deprecated features

reaction.delete has been deprecated in favor of reaction.remove_from_model
overloaded + and += for cobra.Model are deprecated in favor of model.merge