Line management window show convoy load with separate bars for different goods

[DrSuperGood]

A quality of life improvement. With the large number of combined transport ships with integrated mail holds and such it is becoming increasingly difficult to tell how overcrowded a line is by looking at the line managed window. Especially since a ship might hold 20 passengers (important) and 500 mail (unimportant) the result is an overcrowded ship barely shows any green bar on the line manager window.

The suggestion is that each type of good is given a separate bar stacked on top of each other if available. For example passengers might be a blue bar, while mail a yellow bar. This way one would barely see any mail bar visible for such convoys but if the line is overcrowding see a full width blue bar for passengers.

Also a graph for "empty seats" would be useful. Currently the mail holds drown out the total capacity graph making it meaningless.