fix highlight & count by hashing author html

This commit changes highlighting to avoid using innerText.

comments[i].getElementsByClassName('author')[0] would end up putting
the following in the votes array:
 on Chrome:
<a href="/someuser" class="author">someuser</a>
 on Firefox:
<a class="someuser" href="/someuser">

Adding innerText works only on Chrome and it would add "someuser" to
the votes array.
Merge pull request #3 from unclejack/fix_issue_highlighting

fix highlight & count by hashing author html