Check CRW bearing is not leading to bias towards horizontal movement

Note to self:

The use of a correlated bearing was intended to simulate that fishers would pass back over a "good" patch of fish, but may have unintentionally introduced a bias towards horizontal over vertical exploration. Need to check and correct if so... 

https://github.com/pdolder/MixFishSim/blob/32e2c26fa1561acaad229aa5e8b7464df5cc9fd7/R/get_bearing.R#L28