add bst_base template

	modified:   tf/avltree.hpp
	new file:   tf/bst.hpp
	new file:   tf/countable.hpp
	new file:   tf/hasvalue.hpp
	new file:   tf/main.cpp.autosave
	modified:   tf/node.hpp
	new file:   tf/node.hpp.autosave
	modified:   tf/rbtree.hpp
	modified:   tf/splaytree.hpp
	new file:   tf/splaytree.hpp.autosave
	modified:   tf/tf.pro
	modified:   tf/tf.pro.user