v0.4.1

v0.4.1:

• fix failing tests in notebooks (no Travis tests for ISIS functionality possible for continuous integration)
• add __version__ info to pyciss
• remove private notebooks from GH repo

v0.4.0:

• Refactoring opusapi methods
• refactoring io.RingCube into pyciss.ringcube. Should now be called as pyciss.ringcube.RingCube()
• adding test notebooks for opusapi.