Find the coefficients of the plane equation

plane_coefficients(p, n)

p | A point on the plane (or N x 3 matrix of multiple points) |
---|---|

n | vector normal to the plane (or N x 3 matrix of multiple vectors) |

a matrix with 4 columns `a,b,c,d`

where ```
ax + by + cz + d =
0
```

Both `p`

and `n`

can accept multiple points/vectors to
calculate many planes at once.

Other geometry:
`intersect_plane()`