Enhancement Proposal: Table Markup

As I like having tables readable, I just added a little markup to the tables.

You might add this to style.css, or add an option in the customize menu to enhance the table style.

thead tr:last-child th,
tr:last-child td {
       border-bottom: 2px solid;
}
tr:nth-child(5n+5) td {
       border-bottom: 1px solid;
       border-color: #999;
}
tr td {
       border-bottom: 1px dashed;
       border-color: #999;
}