[nautilus-python] (17 commits) Non-fast-forward update to branch wip/jtojnar/nautilus-4

[Jan Tojnar <jtojnar src gnome org>]

The branch 'wip/jtojnar/nautilus-4' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  2886d66... build: Add meson build system
  e98f5d3... Remove autotools
  0376074... Port to libnautilus-extension-4
  8faba39... Implement NautilusPropertiesModelProvider support

Commits added to the branch:

  2622a8d... build: Add meson build system (*)
  2775cf3... Remove autotools (*)
  132384b... docs: Fix page titles in Devhelp (*)
  5049e1c... nautilus-python-object.c: Remove the extra reference on the (*)
  49e5869... README: Convert to Markdown and modernize (*)
  d187ffb... Drop Python 2 support (*)
  561d3e4... Fix memory leaks noticed by Nemo (*)
  8908c47... python-object: Fix a memory leak (*)
  908363c... examples: install TestExtension (*)
  991754d... examples: Call GObject constructor in our constructors (*)
  3cfb7b8... examples: Add type annotations to methods (*)
  183a6cd... python-object: Fix more memory leaks (*)
  c437145... NEWS: Port to Markdown (*)
  f664378... docs: Fix links to examples (*)
  fac72de... Port to libnautilus-extension-4
  652341e... Implement NautilusPropertiesModelProvider support
  ec2e1e6... docs: Add 4.0 migration guide

(*) This commit already existed in another branch; no separate mail sent