some enhancements for the site extension

with the dispedia development i have made some enhancements for this extension, here is a little overview

* first I added language support for *literal* and *img* helper. It's useful if you have different language on the website and the extension should use the statement in the selected language

* the second feature is, that the *sites* folder are now really changeable. Before you was able to change the folder in the doap file, but the references to this folder are still alive, because the are hard coded in the controller, now you are able to really change the folder to any place you want (also outside the extension)

* the third one is a table helper, so you can add specific statements to the site model and the helper generate a table from this statements (also with language support, like the first feature). To use this you have a main property, like this
```http://ns.ontowiki.net/SysOnt/Site/tableContent```, then the cells were filled with the content of the following properties
```
http://ns.ontowiki.net/SysOnt/Site/tableContentR1C1
http://ns.ontowiki.net/SysOnt/Site/tableContentR2C1
http://ns.ontowiki.net/SysOnt/Site/tableContentR1C2
```
and the size will be set by
```
http://ns.ontowiki.net/SysOnt/Site/tableContentRows
http://ns.ontowiki.net/SysOnt/Site/tableContentColumns
```
With this you can generate a table and can change the content and the size dynamically. I don't know if this is a correct or good semantic representation of a table, but anyway i needed a table one the website.
If you want to look at a example, look at www.dispedia.de.

Maybe you want to include some of this features, feel free to do it. :)