Include a way shift polarity of binaural beats.

[Mr-Kumar-Abhishek]

There should be a way to shift polarity of binaural beats.

This would require:

1. A function that will switch left and right channel frequencies
2. A UI element which will be the switch for shifting polarity

[Mr-Kumar-Abhishek]

The polarity shift UI should included in volume box section of the UI.