v0.6.0

What's Changed

• update RELEASING.md by @joeferner in #77
• pwm: settle after a duty write, or two in a row are both lost by @joeferner in #78
• document mailbox source information by @joeferner in #80
• mailbox: add display enumeration and selection by @joeferner in #81
• update docs by @joeferner in #82
• add Pi 1 / Pi Zero support (BCM2835, ARMv6) by @joeferner in #83
• release 0.6.0 by @joeferner in #84

Full Changelog: v0.5.0...v0.6.0