more decoupling editor tests from App

Dependencies

• [2] CIQN2MDE bugfix: typing a capital letter deletes selection
• [3] 7EQLPB3O bugfix: don't delete selection when moving cursor
• [4] LNUHQOGH start passing in Editor_state explicitly
• [5] M6TH7VSZ rip out notion of Line_width
• [6] 2JLVAYHB start decoupling editor tests from App
• [7] APYPFFS3 call edit rather than App callbacks in tests
• [8] EMHRPJ3R no, that's not right
• [9] LF7BWEG4 group all editor globals
• [10] 4WAFGF4Z selection bugfix
• [*] LXTTOB33 extract a couple of files

Change contents

• replacement in text_tests.lua at line 481
  [3.401]→[3.401:429](∅→∅)
  − App.keyreleased('lshift')
  [3.401]

  [3.429]
  + edit.key_released(Editor_state, 'lshift')
• replacement in text_tests.lua at line 537
  [2.465]→[2.465:487](∅→∅)
  − App.keypressed('d')
  [2.465]

  [2.487]
  + edit.keychord_pressed(Editor_state, 'd', 'd')
• replacement in text_tests.lua at line 539
  [2.508]→[2.508:531](∅→∅)
  − App.keyreleased('d')
  [2.508]

  [2.531]
  + edit.key_released(Editor_state, 'd')