Allow multiple fields to be incremented properly

I've wrapped the $input in an each loop to capture all the fields that would be cloned and this would make way to multiple fields being cloned properly in terms of name and id field.

Initially, the current javascript code treats multiple fields to have the same input name and id.

So if there is this fields:
<input type="text" name="field[0][url]" value="" />
<input type="text" name="field[0][name]" value="" />

If cloned, it would end up like this:
<input type="text" name="field[1][url]" value="" />
<input type="text" name="field[1][url]" value="" />

The above proposed fix will fix this issue.
Fix cloned radio inputs

Fix #1: Upon cloning radio inputs, the problem is inconsistency on previously cloned radio would loss its checked attribute if "checked".

Fix #2: $(this).val( '' ); will be improper for radio inputs as radio inputs depends on its value. Please see changes.

Thanks and God bless!
ThemePlugger
Fix cloned checkbox inputs
Fix cloned checkbox inputs *Final
Merge pull request #458 from ThemePlugger/patch-1

Allow multiple fields to be incremented properly