Merge branch 'master' into ng/master

Merge branch 'master' into ng/master

* master:
  self checks: avoid spurious failures when keep_testdirs=yes
  fixup: some weaknesses in a self-check test case
  maintcheck: avoid yet more spurious failures (2)
  maintcheck: avoid yet more spurious failures (1)
  hacking: fixlets w.r.t. the release procedure
  maintcheck: fix spurious failures
  maint: version bump after beta release
  Beta release 1.11b (will become 1.12)
  sync: some auxiliary files synced from upstream
  hacking: described new branching policy for 1.12 an later
  vala tests: avoid spurious failure with older GObject

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>