1.7.0
~~~~~

- now specific generators can be called outside the tree search to strengthen
your formulation with the generate_cuts method. This is a CBC only feature
(Gurobi does not allow access to its cut generators).

- A stability fix for CBC is included: in some cases an incorrect
solution/optimization status was produced in searches truncated by time.

1.6.0
~~~~~

- selection of which linear programming method (Primal Simplex, Dual Simplex or
  Barrier) will be used to solve the root node relaxation (lp_method attribute
  of Model)

- read/write property RHS in Constraint

- pytest for tests - thanks @pmla

- do not throw exception when querying an unavailable solution: just return
  None instead, to fix problem in some debuggers 

- improved documentation - specially for the examples




