1335 final allow discharge in swmmoutf dat with 3 values 01and 2

[FLO-2DJJ]

• New Outfalls dialog with allow discharge as combobox with 0,1,2 values:

• Reading allow discharge from a shapefile as 0,1,2.

[FLO-2DJJ]

@FLO-2DKaren

This pull request completes the logic for Allow Discharge.

Maybe, the only thing you have to change in the documentation is the picture of the outfalls dialog with a new dropdown list for allow discharge:

It can now be merged without conflicts.

[FLO-2DJJ]

@FLO-2DKaren, @FLO-2DNoemi Please review and merge if approved. I tested it and look fine. No conflicts at this time with master.

[FLO-2DJJ]

Ready to merge.