… and no other changes to pandapipes

…op correctly everywhere

…low and temperature spread the missing value is calculated. Changed variable names from _k to _c since temperatures are stored in °C. Added simulation results to .gitignore.

…, mass flow and circuit temperature which is to remain constant and which will be passed to the time step initialization functin are defined when initializing the object es a flag. Values of parameters and physical constant are adapted to the values used in parantapas model in order to assure comparibility

…ize_time_step - function in __init__. Raise warnings in functions to calculate mass flow or temperature spread if necessary.

…d order of strata in model. Set physical quantities to values defined in fmu model.