FIX: Add ; after &laquo &raquo, modal moved in tr

[dragon-fire-fly]

Following basic testing with https://validator.w3.org/ , some minor changes made including:

• add semicolon after &laquo and &raquo
• change display value to visibility so that table column can be hidden on smaller screen sizes
• remove trailing / at the end of <input> elements
• Modal for deleting messages moved inside <td> element for HTML compliance ( <div> elements should not be inside <table> elements.)