games/burr-tools: update to 0.7.0

• project has moved to github
• project now builds with meson
• rename from burrtools to burr-tools to match repository name
• docs require Python 2.7 to build. As per policy, I have thus not packaged them.

Changelog: https://github.com/burr-tools/burr-tools/releases/tag/v0.7.0