Update tox & travis; README fix; theming fix

[econchick]

• Updated tox to always do coverage for coveralls
• Updated travis for PyPI deployment
• Attempting to fix RTDs importing of theme to use my hack of a spotify theme
• Links to external RTDs from README
• Adjust badge targets

[coveralls]

Changes Unknown when pulling c8d6fa256d6719066b01dc4ca85d60f48e37b098 on econchick:master into \ on spotify:master**.

[coveralls]

Changes Unknown when pulling c8d6fa256d6719066b01dc4ca85d60f48e37b098 on econchick:master into \ on spotify:master**.