fixed remove() to get rid of removed element refs

removes from $self and from all $self->{before}.

Also modified how each() instantiates the objects, so $_->end works in the callback, which is needed for $_->remove() to work in the callback.
now storing comments from parsed html
added t/store_comments.t, and fixed html() to store comments
added clone() method
changed clone() not to use HTML::Element directly
Merge pull request #14 from cafe01/clone

clone() method
Merge pull request #13 from cafe01/storecomments

Store comments
Merge pull request #12 from cafe01/removebug

fixed remove() to get rid of removed element refs