module Kramdown::Options

names are considered and their value is run through the #parse method.
Merge the #defaults Hash with the *parsed* options from the given Hash, i.e. only valid option

def self.merge(hash)
  temp = defaults
  hash.each do |k, v|
    k = k.to_sym
    temp[k] = @options.key?(k) ? parse(k, v) : v
  end
  temp
end