Hyper link in readme is broken.

[m-d-grunnill]

A line in the readme is broken. It reads:
"""
An example of using the Python class can be found in the beast2-xml.py script. Small examples showing all functionality can be found in the tests in test/testBeast2.py.
"""

It should be:
"""
An example of using the Python class can be found in the beast2-xml.py script. Small examples showing all functionality can be found in the tests in test/test_Beast2.py.
"""