Table width incorrect when "Field List" collapse

When the field list for a table is minimized an extraneous span12 class is added to the table-main element. This causes the table to overflow the boundary of the panel.

![screenshot from 2014-03-11 08 30 46](https://f.cloud.github.com/assets/41702/2387052/ecc19618-a932-11e3-9218-06c60d0e2f28.png)