optimization.py: Fix "epsilons" keyword argument in _optimize() (#150)
optimization.py: Fix "epsilons" keyword argument in _optimize() (#150)

The keyword argument "epsilon" isn't used anywhere else in the EMAworkbench, it should be epsilons (with an s).

So currently if doesn't throw an error when you define a list of epsilons of the wrong length, because it searches for epsilon instead of epsilons. This commit fixes this.
quaquel/EMAworkbench,quaquel/EMAworkbench