#73 show only one "reply-form" at a time

A click on a post brings up a new "reply-to" input field. If another post is clicked, the previous "reply-form" should be closed first
fixed #78 duplicate ids for "text" field

After we fixed the first step of #73, there can only be a single "reply-form" on a page at a time. Therefore giving this reply-form's input field a unique id (different from the "entry-form") should fix the duplicate id issue.