v0.8.0: New Variable/Parameter naming system

• added mapping functionalities that allow to use the pyrates-based names for variables and parameters in the model rather than the auto naming style
• implemented the changes with the ODESystem.run and ODESystem.extract methods
• dataframes return by ODESystem.run now contain the pyrates-like variable names in the column header
• ODESystem.__init__ now takes a couple of new arguments: The "eq_file" is a positional argument that ties an ODESystem instance to a single fortran equation file. "params" and "state_vars" allow to provide the parameter and state variable names that can be used instead of the indexing style of auto.
• the parameter and state-variable names that can be provided to the ODESystem.__init__ method can be directly obtained from the CircuitTemplate.get_run_func that is also used by the ODESystem.from_yaml method.