Print parameter position when showing DAME command

[dgarijo]

If for some reason you want to mess up and test with the parameter values in DAME, the parameter positions should be shown in the invocation as well. For example, right now DAME shows:

Parameters
- weed_fraction: 0.05
- use_forcing: FALSE
- end_planting_day: 149
- end_year: 2017
(other parameters omitted for brevity)

What it should show:

Parameters
- weed_fraction (p1): 0.05
- use_forcing (p2): FALSE
- end_planting_day (p3): 149
- end_year (p4): 2017
(other parameters omitted for brevity)

Where p1..p4 are the parameters that will be shown in the invocation command. E.g.,:

-i2 crops.crop  -o1 cycles_soilProfile.dat -o9 cycles_outputs.txt -o3 cycles_crop.dat -o5 cycles_season.dat -o2 cycles_som.dat -o8 cycles_water.dat -o4 cycles_nitrogen.dat -o7 cycles_weatherOutput.dat -o6 cycles_summary.dat  -p4 100 -p2 2017 -p6 0 -p3 Maize -p5 149 -p8 FALSE -p7 0.05 -p1 2000```