v0.5.0 Somewhat nicer plots

Small update featuring some better looking plots (though still a work-in-progress, see #240) and a documentation fix.

What's Changed

• Bump version to 0.5.0 by @jfrost-mo in #278
• Improve contour plot by @jfrost-mo in #282

Full Changelog: v0.4.0...v0.5.0