Exercise Event Logger

A simple example on how we can log events and nice to
see which ones are possible.
Changed hardcoded paths

There are several paths in the code we need to change
to be able to access all the files next to the Curriki web app
Style adoptions and tailoring

The delivered templates and css are not in the needed width
 and shape. Add some css changes to adopt the exercise
 panel to Curriki needs.
Mavenize

Add a pom.xml so this is a maven module now. Yay!
The build of the module currently contains only the files
which are needed for the Curriki web app.
Readme changes.

Throw out the khan readme (well still link to it). Create a
separate readme for this forked module.