allow users to provide library version

[arun3688]

Related issues

#44

Purpose

This PR allows users to provide library Versions using the ModelicaSystem constructor

Example

>>> ModelicaSystem(omc, "TestVersion.mo", "Test", ("Modelica","3.2.3")) # usage 1 as a tuple
>>> ModelicaSystem(omc, "TestVersion.mo", "Test", [("Modelica","3.2.3")]) # usage 2, as array of tuples 
>>> ModelicaSystem(omc, "TestVersion.mo", "Test", [("Modelica","3.2.3"), "PowerSystems"]) # usage 3, as Array of tuples and  String