Adds CoverTree implementation

src/algorithm/neighbour/mod.rs

@@ -0,0 +1,11 @@
+pub mod cover_tree;
+pub mod linear_search;
+
+pub enum KNNAlgorithmName {
+    CoverTree,
+    LinearSearch,
+}
+
+pub trait KNNAlgorithm<T>{
+    fn find(&self, from: &T, k: usize) -> Vec<usize>;
+}