v0.3.1

• Respect PERF and DTRACE environment variables to support custom paths (#92, thanks to @spitfire05)
• Restore the default sample rate of 997 (#90, thanks to @yoshuawuyts)
• Upgrade inferno to 0.9.8 (#87, thanks to @SoftwareApe)
• Don't optimize build-time dependencies (#89, thanks to @joshtriplett)