More convenient calls of coordinate maps

[szabo137]

Currently, the calls for coordinate maps depend on the psl, which was passed in the construction:

# Create a coordinate map for in-phase space
in_coord_map = CoordinateMap(proc, model, in_psl)

# call on in-coordinates to build the momenta
in_coord_map(in_coords)

# Create a coordinate map for out-phase space
coord_map = CoordinateMap(proc, model, out_psl)

# Call on in- and out-coordinates to build the momenta
coord_map(in_coords, out_coords)

However, it would be very convenient to return the in-momenta also on call of the coord_map:

# Create a coordinate map for out-phase space (which contains the in_psl by design)
coord_map = CoordinateMap(proc, model, out_psl)

# Call on in- to build the in momenta
coord_map(in_coords)