Implementing searching and pulling docker images

The problem is the CSS:

```
#containers-search-image-results {
     display: block;
     height: 300px;
     overflow-y: scroll;
     border: 1px solid #BABABA;
     margin-top: 10px;
 }
```

It's a table so the "display" property should be "table", not "block".  I propose to replace the HTML with this:

```
<div class="modal-body">
  <input type="search" class="form-control" id="containers-search-image-search"/>
  <div id="containers-search-image-waiting"></div>
  <div id="containers-search-image-results">
    <table class="table table-hover">
      <tbody/>
    </table>
  </div>
</div>
```

Note the "table-hover" class.  That way we don't need the ```#containers-search-image-results tr:hover``` style.

(The explicit ```tbody``` element is unexpected but seems to be needed by insert_table_sorted_generic.)