[python] Properties file in python (similar to Java Properties)

This is a one-to-one replacement of java.util.Propeties

From the doc:

  def __parse(self, lines):
        """ Parse a list of lines and create
        an internal property dictionary """

        # Every line in the file must consist of either a comment
        # or a key-value pair. A key-value pair is a line consisting
        # of a key which is a combination of non-white space characters
        # The separator character between key-value pairs is a '=',
        # ':' or a whitespace character not including the newline.
        # If the '=' or ':' characters are found, in the line, even
        # keys containing whitespace chars are allowed.

        # A line with only a key according to the rules above is also
        # fine. In such case, the value is considered as the empty string.
        # In order to include characters '=' or ':' in a key or value,
        # they have to be properly escaped using the backslash character.

        # Some examples of valid key-value pairs:
        #
        # key     value
        # key=value
        # key:value
        # key     value1,value2,value3
        # key     value1,value2,value3 \
        #         value4, value5
        # key
        # This key= this value
        # key = value1 value2 value3

        # Any line that starts with a '#' is considerered a comment
        # and skipped. Also any trailing or preceding whitespaces
        # are removed from the key/value.

        # This is a line parser. It parses the
        # contents like by line.