added a quit function to the shell environment, for obvious purposes

lib/shell.lua

@@ -21,6 +21,9 @@ end
 function shell.interactive()
  local shenv = setmetatable({}, {__index=shindex})
  local run = true
+ function shenv.quit()
+  run = false
+ end
  while run do
   io.write(string.format("\27[32m%s:%s>\27[0m ",os.getenv("HOSTNAME") or "localhost",(os.getenv("PWD") or _VERSION)))
   local input = io.read()