Remove new trailing line and empty value for settings file parsing

[toxinu]

Parsing settings file like that failed cause of 2 bugs.

[flake8]
ignore = 
  D100,
  D102,

• \n must be remove because Flake8Lint will send to flake8 an ignore list like that: ['D100\n', 'D102\n']
• Last comma separator will failed because Flake8Lint will send to flake8: ['D100', 'D102', ''] and empty value will ignore all other error codes