added pre-order, in-order, and post-order recursive calls
Added tests for DFT
Merge remote-tracking branch 'origin/DFT' into DFT
Merge bst file to contain both the balance fucntion and the dft
Conflicts:
	bst/bst.py
Add breadth-first generator function and test
Merge pull request #20 from johnshiver/DFT

Dft