Impossible to loop on a range with a float step

[lesquoyb]

Describe the bug
Somewhere between a bug and an enhancement request. Currently the loop statement used with facets from to and step assumes integers as values and casts the floats into int. But why ? It is very inconvenient if you have to convert your range into an integer range to initialise the loop and then do the conversion back to your float working value inside the loop. It also leads to infinite loops if the step value in ]-1, 1[ as it's going to be casted to 0. The worst part is that there's no warning when giving a float to those facets that the values are going to be casted to int.

To Reproduce
Steps to reproduce the behavior:

1. Run:

model NewModel

global {
	init {
		loop i from:1.5 to:10.0 step:0.99 {
			write i;
		}		
	}
}

experiment name type: gui {
}

2. Observe the infinite loop and that i's value is 1 instead of 1.5

Expected behavior
Either the loop accepts floats, or at least it gives warning for the casting it is going to do