v1.6.0

ABI summary:

• mirserver ABI bumped to 52
• mirplatform ABI bumped to 17

Enhancements:

• [mirclient] Drop some more mirclient support: infrastructure, unit-tests
• [Wayland] Avoid unnecessary calls into Window Management (Fixes #1049)
• [graphics-platforms] Improve diagnostics by running the platform probe even when manually selected. (Fixes #1045)
• [graphics-platforms] Provide a generic way to handle the Wayland buffer consumption
• [graphics-platforms] tests: Add basic manual platform test harness
• [graphics-platforms] Add "Wayland platform"
• [graphics-platforms] Initial rpi-dispmanx platform
• Drop the --wayland-socket-name (redundant) configuration option
• New mir_demo_client_wayland_egl_spinner in mir-tests-tools package
• New miral-system-compositor in mir-demos package

Bugs fixed:

• Crashes & lockups caused by thread-unsafe code. (Fixes #1106)
• Mir crashes when surface sets parent to null. (Fixes #1053)
• Fix build against GMock/GTest ≥ 1.9
• Fix build on Arch (Fixes #1084)