DataStructures/HashTable/HashTable.h: Created a basic hash table data structure.

DataStructures/Trees/BinaryTree/BST/BST.h: Moved file from "DataStructures/Trees/BST.h". Explicitly initialized the root node to null in the default constructor.

DataStructures/Trees/BinaryTree/BTNode.h: Moved file from "DataStructures/Trees/BTNode.h".

DataStructures/Trees/BST.h: Moved file to "DataStructures/Trees/BinaryTree/BST/BST.h".

DataStructures/Trees/BTNode.h: Moved file to "DataStructures/Trees/BinaryTree/BTNode.h".

README.md: Added TODO note about hash table collision resolution.