Finding versions of the Abjad toolchain

Use the following commands to find versions of Abjad tools:

$ lilypond --version
GNU LilyPond 2.15.3 ...

$ python --version
Python 2.6.1

$ py.test --version
This is py.test version 2.1.0 ...

$ sphinx-build --version
Sphinx v1.0.7 ...

$ less `which easy_install`
... __requires__ = 'setuptools==0.6c9' ...

$ svn --version
svn, version 1.6.17 ...