check_mol() in Docker classes need discussion and validation

[BrandeisPatrick]

Explanation of check_mol()

check_mol() is a type of methods every Docker classes have.

Docker classes take molecule object or objects as input parameters. check_mol() checks if the input objects have required attributes for the following procedures in Docker classes.
For example. it will check molecular.pdb molecular.frcmod molecular.lib etc

Issue

1. I do not know what attributes are required for each Docker class.
2. Solutes and solvents need to be treated differently. Different attributes may be required by Docker classes.

Current Situation

1. I have made some check_mol() only check molecule.name, molecule.residue_name .. some common properties
2. .frcmod .mol2 are not checked