Property stream format:

line separator is \r?\n.  1 line per a property.
line which begins with '#' is a comment line.  empty line is ignored, too.
key/value separator is ':' or '='.
'\' as escape character.  but line separator cannot be escaped.
\s at the head/tail of key/value are trimmed.

'[' + key + ']' indicates property section.  for example,

  [aaa.bbb]
  ccc = ddd
  eee.fff = ggg
  []
  aaa.hhh = iii

is the same as;

  aaa.bbb.ccc = ddd
  aaa.bbb.eee.fff = ggg
  aaa.hhh = iii