Deploy to pypi only once when using build matrix

Makes use of TravisCI build stages. Note that this feature is still
in beta.

Master

Dev 2.5.0

Added screwless  camera design to documentation

Fix links in badges to point to wroscoe:dev

Handling code quality and dependency upgrades

- Use conda as build environment
- Add test dependencies to extras_require
- Add code coverage (coverage and codecov.io)
- Update badges in README

# Conflicts:
#	setup.py