bugfix: on.load_settings when there are none

Dependencies

• [2] W3UFZ4FO run on.load_settings after loading defaults
• [3] MPETAKZ2 insert space for loading settings
• [4] 36Z442IV back to commit 8123959e52f without code editing
• [5] 7RDQRRP5 Merge text0
• [*] OTIBCAUJ love2d scaffold
• [*] DSDKFEUK persist window geometry to disk across restart
• [*] 5OVKHVY6 nice way to make on.* handlers more discoverable
• [*] FRXBX5FC create space for app-specific settings

Change contents

• edit in main.lua at line 81
  [8.747]

  [3.51]
  + if on.load_settings then on.load_settings(settings.app) end
• edit in main.lua at line 95
  [3.729]

  [3.729]
  + if on.load_settings then on.load_settings() end
• edit in main.lua at line 97
  [3.735]→[2.8:70](∅→∅)
  − if on.load_settings then on.load_settings(settings.app) end
• edit in 0001-on at line 19
  [10.227]

  [10.227]
  + -- settings might be nil if there are no saved settings