stop confusingly reading a global

Dependencies

• [2] KURLAXXI clean up some prints
• [3] Y4SPXCM3 bugfix: pagedown was sometimes bouncing up
• [4] 3ZSUBI57 drop some redundant args from Text.draw
• [5] HALS7E5U more clearly skip prints before screen top
• [6] MYC7XR5Q bugfix: lines that aren't drawn from the start
• [7] ILOA5BYF separate data structure for each line's cache data
• [8] 6WDBV52Z move a var closer to its use
• [9] H2DPLWMV snapshot: wrapping long lines at word boundaries
• [10] CVGE3SIG I feel confident now that page-down is working.
• [11] LERERVPH keep one screen line of overlap on pagedown
• [12] 2ZRC7FUL .
• [13] DHI6IJCN selecting text and deleting selections
• [14] MXA3RZYK deduce left/right from state where possible
• [15] HGC5RGJP switch to line index in a function
• [16] GK47BBCY start passing left/right margins everywhere
• [17] X3F7ECSL add state arg to some functions
• [*] BULPIBEG beginnings of a module for the text editor

Change contents

• replacement in text.lua at line 20
  [4.1818]→[3.750:807](∅→∅)
  − local screen_line_starting_pos = State.screen_top1.pos
  [4.1818]

  [4.3821]
  + local screen_line_starting_pos = startpos
• replacement in text.lua at line 29
  [2.73]→[4.3:71](∅→∅),[4.334]→[4.3:71](∅→∅)
  − if Text.lt1({line=line_index, pos=pos}, State.screen_top1) then
  [2.73]

  [4.71]
  + if pos < startpos then