Py3: make 'Generator/ODESystem.py' compatible with Python 3.3
Py3: make 'Generator/Euler_ODEsystem.py' compatible with Python 3.3
Py3: make 'Generator/Vode_ODEsystem.py' compatible with Python 3.3
Py3: make 'scipy_ode.py' compatible with Python 3.3
Py3: make 'Generator/Dopri_ODEsystem.py' compatible with Python 3.3
Py3: make 'integrator.py' compatible with Python 3.3
Py3: make 'Generator/Radau_ODEsystem.py' compatible with Python 3.3
Py3: make 'ModelSpec.py' compatible with Python 3.3
Py3: make 'fixedpickle.py' compatible with Python 3.3

There are a lot of changes. Needs testing!
Py3: make 'Generator/ExplicitFnGen.py' compatible with Python 3.3
Py3: make 'Generator/ImplicitFnGen.py' compatible with Python 3.3
Py3: make 'Generator/LookupTable.py' compatible with Python 3.3
Py3: make 'Generator/InterpolateTable.py' compatible with Python 3.3
Py3: make 'Generator/ExtrapolateTable.py' compatible with Python 3.3
Py3: make 'Generator/MapSystem.py' compatible with Python 3.3