Added 'rowspan' attribute to 'loading info' TD element of AbstractJQuery...

Hi Manu and others,
  I tried to figure out broken table layout caused by AbstractJQueryTable component. I found that the missing 'colspan' attribute resulted in incorrect display of tables with different background than the background of the underlying element. See provided screenshots before/after change.

![correct_behavior](https://f.cloud.github.com/assets/1846145/1257126/361b8e54-2ba2-11e3-81b7-f4246ef7e49c.png)
![bad_behavior](https://f.cloud.github.com/assets/1846145/1257127/3644bed2-2ba2-11e3-8b06-34b431371b9f.png)

PS: this is my first pull request on github ever, so please be lenient :)