t8code pre-release v.0.11.0

Added CITATION file.

What's Changed

• Add ~ Files to gitignore by @holke in #288
• Develop by @holke in #287
• increase version number in tests by @holke in #289
• Develop by @holke in #292
• Feature citation file by @Niklas997 in #290

Full Changelog: v0.10.0...v0.11.0

t8code pre-release v.0.10.0

We are preparing the release of version 1.0.0

This release is a stable release of t8code.