bugfix: don't append metadata when it already exists

Dependencies

• [2] PESSMQBJ no, make sure to compute line width after screen dimensions
• [3] R53OF3ON one bug I've repeatedly run into while testing with Moby Dick
• [4] ESETRNLB bugfix: printing the first part of a line at the bottom made it seem non-wrapping
• [5] MDXGMZU2 disable all debug prints
• [6] PR4KIAZD first stab at equally hacky cursor down support
• [7] AIRIP35Z cleaner
• [8] BULPIBEG beginnings of a module for the text editor
• [9] 2RXZ3PGO beginning of a new approach to scroll+wrap

Change contents

• replacement in text.lua at line 977
  [3.1794]→[3.1:63](∅→∅)
  − screen_lines = Lines[Cursor1.line].screen_line_starting_pos
  [3.1794]

  [3.1454]
  + local screen_lines = Lines[Cursor1.line].screen_line_starting_pos
• edit in text.lua at line 1220
  [2.101]→[3.2209:2250](∅→∅),[3.2209]→[3.2209:2250](∅→∅)
  − -- duplicate some logic from Text.draw
• edit in text.lua at line 1221
  [3.2283]

  [3.2283]
  + if line.screen_line_starting_pos then

  + return

  + end

  + -- duplicate some logic from Text.draw
• edit in text.lua at line 1240
  [3.2751]

  [3.2751]
  + --? print(' ', #line.screen_line_starting_pos, line.data)