Accessing dicts with jl.Symbol keys from python

[havahol]

Several of the objects from JutulDarcy has field that can be accessed through using a Julia Symbol as a dict key. An example:

state[:Reservoir][:Pressure]

Accessing these fields from Python becomes quite verbose:

state[jd.jl.Symbol('Reservoir')][jd.jl.Symbol('Pressure')]

We should either update JutulDarcy.jl to accept strings as keys as well, or find a less verbose access method on the Python side

Encountered objects (from PR #3) for this issue in PyJutulDarcy:

• DataDomain objects
• MultiModel objects
• The return value from setup_reservoir_state which is a Dict{Any, Any}. For this specific one, perhaps the wrapper should call symdict_to_pydict before return?

For examples, see notebook/equilibrium_state.ipynb and set_secondary_variable! wrapper from PR #3.