add messages to inform user of column limits & change cursor of buttons

Made the following changes to theme "pfsense_ng_fs":

* Added "alt" & changed the cursor to be a pointer on the add and delete column imgs
* added the following to be inserted via jQuery

```<div id=\"columnWarningText\" style=\"float:left; margin-left:5em\"></div>```

This allows messages to be displayed to the user via jQuery...

* Added messages to the user that the maximum (10) & minimum (2) number of columns have been reached when a user tries to add/delete more columns (clicks the buttons).

commit 0a819f2 is just indentation and adding a single comment - no code change

@rbgarga