Print binary heap in tree form

[adeet1]

This pull request improves the print() method in binary_heap.cpp by printing the heap as a tree instead of as an array, making it easier to visualize the heap.

createTree() is a helper method, which iterates through each element in the heap array to create a binary tree from the array.

Notes:

1. The print functionality itself is taken from lab 5.
2. Please ignore commit 05dc0cb, as it is a duplicate of the commit in the previous pull request.