Calculate compound growth with inflection points.
Example:
var GrowthCurve = require('growth-curve');
var killerGrowth = new GrowthCurve({ "1": 1.02, "5": 1.10, "25": 1.20, "46": 2 });
var healthAt47 = gentleGrowth.growTo(100, 47);
var rateAt33 = gentleGrowth.getRate(33); // returns 1.2
###Constructor ####new GrowthCurve( inflectionPoints ) inflectionPoints is an object with rules governing the compound rates at the iterations where they change.
###Methods ####growTo( initial, target ); Returns the value of initial after it has been compounded target number of times with changes to the rate set according to the rules given in the constructor.
#####getPoint( target ); Returns the point that the growthCurve would use at the target iteration.
#####getRate( target ); Returns the rate that the growthCurve would use at the target iteration.