map(value, istart, istop, ostart, ostop)
Re-maps a number from one range to another.
Numbers outside the range are not clamped to 0 and 1, because out-of-range values are often intentional and useful.
Type: function
Parameter(s):
- value {Number}:
The value to be mapped.
 - istart {Number}:
The start of the input range.
 - istop {Number}:
The end of the input range.
 - ostart {Number}:
The start of the output range.
 - ostop {Number}:
The end of the output range.
 
Returns:
- 
    {Number}:
The mapped value.