Remove addtime default and add ability to compute kth distance

[lingyiyang]

There are two suggested changes:

1. Remove the addtime augmentation as a default. The data that users input may already have a time channel, and this default behaviour is unexpected. Some existing examples may have to be altered.
2. Change the computation of the conformance score to include an extra parameter called kth, this enables us to find the kth closest neighbour rather than always returning the nearest neighbour. This is in addition to the n_neighbors parameter as the latter finds n neighbours in the projected subspace, once the distance away from the subspace is taken into account, the ordering of the neighbors will change.