added test file for binary search tree
first test passing
first test passing
two test passing, can insert left
two test passing, can insert left
three tests passing, insert left when equal
four tests passing, can insert right
five tests passing, complete tree working
six tests passing, can seach single element tree
six tests passing, can seach single element tree
seven tests passing, 2 element case handled
8 tests passing, 2 elements with one to right handled
all tests passing, full tree can be recorded