Show fluid generation in details for power producers

[Honktown]

A most frustrating thing is trying to balance steam/water systems and not alt-tabbing out to look things up on the wiki. Steam engines and turbines already show fluid consumption at present and maximum. A small mod to add that same feature to steam generators seems reasonable.

Benefits:
1) I can instantly know how many consumers I should have to match generators, instead of using awkward numbers like power produced, especially if mods add different generators/consumers.

2) I can see how active the generators are. Not as useful in a matched/unmatched set-up, but if I have storage tanks, I can see if I'm having throughput issues somewhere (if generators aren't filling fast enough or tanks aren't emptying fast enough and the generators kick on).

3) I can see if I have enough water producers, or throughput issues. At present, one must use the final generators (steam engines, turbines, what have you) to determine if the very front of that chain is enough. You can get a general idea by watching the water value on generators, but it doesn't tell you max consumption or active consumption. In that respect, an addition of adding the in-use value to water pumps would be nice (am I drawing 1200 from one side but 100 from another? Who knows!).