Create a 'main' function

[mcnaughtonadm]

We would like to make the process of running eflux3 as simple as possible. A standard run of our code should be a simple one-liner:

condition_specific_fluxes = eflux3(cobra_model, transcriptomics)

where the condition_specific_fluxes and transcriptomics are either pandas dataframes or dict, and the cobra_model is a cobrapy compatible model.

We can also have named arguments such as reference_strain, solver, etc.

Note: We should allow for output type to be single valued fluxes versus triangular distribution parameters (lower,center,upper).