Revert "Merge pull request #39 from dhruv13J/KDTree"

This reverts commit 42c9a54f5afadbb61d27a2da09c6c56c0d0a57de, reversing
changes made to ff34862b9871856a08e80ec6dc3a51983fec56d1.
Revert "Merge pull request #37 from dhruv13J/KDTree"

This reverts commit 082eeb56ea20fc55085950e6114ef4e7849d438d, reversing
changes made to 6615cf007634595d459853bf4dc6f1a227d2450c.
Merge pull request #40 from shogun-toolbox/revert_knn_nanoflann_data

Revert knn nanoflann data