* create and test strategy for generating knn_graph as test inputs
* test strategy for generating knn_graphs
- Each row has the distances sorted in ascending order in the csr-format.
- The indices of the neighbors are unique within a column and don't have the query point as a neighbor.
- If points a and b are mutual neighbors, they have the same distance between them.
* add property based tests for near-duplicate sets
* flag near-duplicate issues based on items in near duplicate sets.
Elías Snorrason