Added test file for util.py

Created and added test_util.py file for testing all functions of
until.py file.
Fixed and updated 2 scripts.

Fixed indentation errors in util.py and updated docstring of
test_util.py
Updated test_util.py

Changed test class name to conform with function name.
Reset testing script for split_phylogeny()

Most updates are concerned with indentations.
Updates with split_phylogeny docstring

Changes made with indentations to conform with the rest of the file.
Merge pull request #3 from akshayparopkari/master

Updates to util.py and test_util.py.