v0.9.1

This is a pre-release tag for dogfooding and packaging purposes.

Changes

• Change ABI from 1 to 0 for libraries that are created - primarily for libmagpie that budgie will build against.
• Remove obsolete magpie.deskop
• Add help-file for magpie-restart-helper to resolve lintian warning
• Fix to actually use magpie-restart-helper for the test magpie wm
• Rebase on mutter 43.6