Mir 0.10.0

- Enhancements:
  . Added support for Android HWC 1.3 devices.
  . Plumbing/preparation to support external displays on Android devices.
  . Reduced build dependencies.
  . Client API: Added version macros.
  . Began work on automatic driver probing, to intelligently choose the
    best driver for you.
  . Demo shell (mir_proving_server): Added desktop zoom feature using
    Super + mouse wheel.
  . Demo renamed: mir_demo_server_shell -> mir_proving_server
  . Other demo servers merged into -> mir_demo_server
  . Wider support for display buffer pixel formats in the mesa driver, for
    wider hardware support.
  . Performance: On mesa/desktop at least; only hold compositor buffers
    for the duration of the render, instead of the duration of the frame.
    Following this change the compositor report can now finally report
    render time instead of frame time.
  . Mir now starts reliably when a TV is connected by HDMI, and up to
    4K resolution (2160p) is known to work.
  . Plenty more enhancements logged in the bugs list below.
- ABI summary: Servers need rebuilding, but clients do not;
  . Mirclient ABI unchanged at 8
  . Mircommon ABI unchanged at 3
  . Mirplatform ABI bumped to 5
  . Mirserver ABI bumped to 28
- Bug fixes: See below.