planckton-flow does not work with SMILES strings as inputs

[chrisjonesBSU]

Describe the bug
I was helping Emily yesterday try and get some simulations going on Bridges while initializing from a SMILES string.

To Reproduce
Enter a simple SMILES string like "CCCCC" in the inputs parameter of init.py

Expected behavior
Compounds to be generated in planckton from a SMILES string.

Additional context
It looks like it's a result of the get_paths() function, which doesn't have any logic to handle SMILES strings from what I can tell.