[dev] finised work on Merk

[Duck]

I finished cleaning and extending Merk for a while. My live case is to list 
articles in 5 different languages and store orders as proforma invoices in 
Minerva. The old internal invoice driver was updated so Merk can still work 
perfectly alone. You can check the link  http://www.microfila.com/shop/  to 
see how looks like. Shipping is closed to Slovenia for now.

Maybe if some will take a little look at the code and clean up some other 
things, Merk could be one of the candidates for starting an release circle. 

Duck