Partial fix https://github.com/morishitter/stylefmt/issues/86

[ghost]

• Partial fix Option to follow only rules described in .stylelintrc #86
  Now when css contain new lines in decl value, stylefmt only format and collaps spaces, but keep new lines

Example:
-- before:

.test {
  font: 'italic small-caps bold 12px arial, sans-serif',14px;

  background: red,
   green , yellow;
  background-color:
    rgba(0, 0, 0, .4),

       rgba(0, 0, 0, 0);
}

-- actual:

.test {
  font: 'italic small-caps bold 12px arial, sans-serif', 14px;
  background: red, green, yellow;
  background-color: rgba(0, 0, 0, .4), rgba(0, 0, 0, 0);
}

And there result is (expected, fixed now):

.test {
  font: 'italic small-caps bold 12px arial, sans-serif', 14px;
  background: red,
    green, yellow;
  background-color:
    rgba(0, 0, 0, .4),
    rgba(0, 0, 0, 0);
}