controlFn: controlFn
In laurieKell/biodyn: Biomass Dynamic Model

A utility function to help set up the control slot in biodyn

1 2	controlFn(r, k, p = 1, b0 = 1, phaseR = 1, phaseK = 1, phaseP = -1, phaseB0 = -1, min = 0.5, max = 2)

`r`	a `numeric` value with best guess
`k`	a `numeric` value with best guess
`p`	a `numeric` value with best guess, default=1
`b0`	a `numeric` value with best guess default=1
`phaseR`	a `numeric` value for phase, default=1
`phaseK`	a `numeric` value for phase, default=1,
`phaseP`	a `numeric` value for phase, default=-1,
`phaseB0`	a `numeric` value for phase, default=-1,
`min`	a `numeric` a multipler for the best guess
`max`	`numeric` a multipler for the best guess