* changes for retrofitting
* changed Snakefile to work with new pypsa-eur version, change solve_network.py to clip also n.generators_t.p_min_pu
* removed retrofitting data files
These are different for residential and services demand.
Also include Snakefile in config files copied for each run.
Use gurobi settings from gurobi support for speed.
Commented out settings for testing randomness for noise.
Heat buses renamed to:
rural (for low-density areas where district heating not possible)
urban decentral (for high-density areas without district heating and
individual heating technologies) (used to be called "urban")
urban central (for high-density areas with district heating) (used to
be called "central")
District heating losses applied only to urban central.