enhancement method of html and append

now html method accept below operations:

1. $$('#target').html("aa");
2. $$('#target').html(["aa", "bb"]);
3. $$('#target').html($$('section'));
4. $$('#target').html($$('section')[1]);
5. $$("#target").html();

append method accept below operations:
1. $$('section.green').append("aa");
2. $$('section.green').append(["aa", "bb"]);
3. $$('section.green').append($$('section')[0]);