Function approx

approx(a: number, b: number, epsilon?: number): boolean
Check if two numbers are approximately equal with a maximum abolute error.
Parameters
- a: number
  Any number
- b: number
  Any number
- epsilon: number = 1e-6
  Maximum absolute error
Returns boolean
True if a is approximately b
Example
```
const b1 = SMath.approx(1 / 3, 0.33, 1e-6), // false
      b2 = SMath.approx(1 / 3, 0.33, 1e-2); // true
```