Function radiansSum

radiansSum(start: number, amount: number, clockwise?: boolean): number
Sum angles together, accounting for the 'wrap around'.

clockwise of true (default) means angles are added in clockwise direction
```
// From 180deg, add 90deg in the clockwise direction
radiansSum(Math.PI, Math.PI/2, true);
```
Orientation of angles is as follows:
```
      90deg
      Pi/2
       |
Pi  ---+--- 0
180    |
      3PI/2
      270deg
```
degreesSum is the same, but uses degrees (0..360)
Parameters
- start: number
  Starting angle, in radian
- amount: number
  Angle to add, in radian
- clockwise: boolean = true
  Add in clockwise direction (default: true)
Returns number
Sum result, in radians