Calls the given block with each successive byte from +self+;
returns +self+:

  'hello'.each_byte {|byte| print byte, ' ' }
  print "\n"
  'тест'.each_byte {|byte| print byte, ' ' }
  print "\n"
  'こんにちは'.each_byte {|byte| print byte, ' ' }
  print "\n"

Output:

  104 101 108 108 111
  209 130 208 181 209 129 209 130
  227 129 147 227 130 147 227 129 171 227 129 161 227 129 175

Returns an enumerator if no block is given.
