Fixing HelpColumn

Trying to close issue #11

Some notes: I was not able to use p.a.jquerytools feature directly (sometimes I really don't understand how this wrapper works). Putting the right code inside ``onclick`` attribute will not open anything.
So: I switched to native jQueryTool overlay features.

I updated the demo example (that was broken) with a public method that can be called using AJAX (not a very nice effect... se image attached) but a real user will be able to call a template or something different.

This is not a very clean solution, but is the only way I found without adding some more JavaScript files.

![schermata 2014-02-04 a 10 11 18](https://f.cloud.github.com/assets/284924/2074576/ffcb8376-8d7c-11e3-895b-ee3ae05b3594.png)