0.2.1

Merged pull requests:

• Enhance release procedure #10 (MartinHjelmare)
• Clean up setup.py #9 (MartinHjelmare)
• Add more tests #8 (MartinHjelmare)
• Format examples in docs #7 (MartinHjelmare)
• Make docs build cleanly and add links #6 (MartinHjelmare)
• Fix readme #5 (MartinHjelmare)
• Add linters to tox and travis #4 (MartinHjelmare)
• Update tox and travis #3 (MartinHjelmare)
• Clean requirements #2 (MartinHjelmare)
• Switch broken pypip.in badges to shields.io #1 (movermeyer)