monte carlo radial mesh

[arturgower]

The radial mesh distance for the monte-carlo method is treated as the centre of a bin, in which the number of particles are counted.

However, if the user provides a mesh with the smallest element too close to zero, then the bin has to change size. At the moment, this line creates an error if the smallest element distance[1] is too close to zero, then the centre of the bin with be negative, and this will lead to mistakes.