Fixes addition of new line at end of the file

Previously a new line was appened at the end of the last line of the file even,
made it so that coala checks first if a new line is present
at the end of the file before appending the last line

Closes coala#6083

coalib/io/File.py

@@ -92,8 +92,16 @@ def lines(self):
  """
  lines = self.string.splitlines()
  if self._newline:
- return tuple(line + '\n'
- for line in lines)
+ line_list = []
+ for line in lines[:-1]:
+ line_list.append(line + '\n')
+
+ newline_end = self.string[-1] == '\n'
+ line_list.append(lines[-1] 
+ + '\n' if newline_end else '')
+
+ return tuple(line_list)
+
  else:
  return tuple(lines)