Syntax highlighting and error handling in Lua console, stdout

[nagydani]

• All operations to standard output such as 'io.write()' must write to the terminal on canvas
• The Lua input should be syntax-highlighted by coloring different lexical elements in different colors:
  • Multi-character keywords in light blue (not cyan!)
  • Single-character keywords in dark blue
  • Number literals in dark magenta
  • String literals in dark green
  • Comments in cyan
  • Identifiers in black
  • Everything behind a parsing error in red
• Errors in lua evaluation should be displayed in the space of the console (i.e. occupying the bottom part of the screen), not corrupting the canvas. They must be visible until a key is pressed; the key pressed must be passed on to the next console input.

[aldum]

• [x] #21 error display
• [x] #22 IO redirection
• [x] #23 syntax highlight