No constructor for NNTree

[KronosTheLate]

From the start of the readme:

The abstract tree type that the trees in this package are a subtype of is called a NNTree. A NNTree is created by the function:
NNTree(data, metric; leafsize, reorder)

However:

julia> using NearestNeighbors; methods(NNTree)
# 0 methods for type constructor:

So one is actually supposed to use another constructor? I am not sure, so I will not make a PR, but as a newcomer, this was very confusing.

[KristofferC]

Can you take a look at #139 and see if it clarifies things?

[KronosTheLate]

Absolutely. It looks great. With #139 merged, this issue is closed.