ensure Filename is writable when opened outside a terminal

Dependencies

• [2] AVQ5MC5D finish uppercasing all globals
• [3] YKRF5V3Z starting to load/save
• [4] IZZVOCLB confirm that we have access to all of the love API
• [5] V5TP27FP ctrl-+ and ctrl-- to adjust font size
• [6] JVRL5TWL store device-independent coordinates inside drawings
• [7] OTIBCAUJ love2d scaffold
• [8] JCSLDGAH beginnings of support for multiple shapes
• [9] QCQHLMST always have a filename

Change contents

• replacement in main.lua at line 60
  [3.4]→[2.342:365](∅→∅)
  − Filename = 'lines.txt'
  [3.4]

  [3.47]
  + Filename = love.filesystem.getUserDirectory()..'/lines.txt'