Absolute delta for phase
Phase is a relative thing measured in degrees. 0.1 degree and 1 degree has delta of 0.9 degree and it's meaningless to say that the second phase is 10 times higher.
- Change the Cavity class to show phase difference in degrees, not in %.
- Implement "wrapping around" property of phase: 179 deg and -170 deg have difference of 11 degrees (and not 349 deg)