class->settext needed the layer name as argument

[assefa]

Initially the class->settext function needed 2 arguments (the first one being 
the layer) : $oclass->settext($layerobj, "new_text").

It should not need the layer argumet since it can be fetched from the class 
object.

[assefa]

Fixed :

 the function now takes only one argument (as already described in the README).

 For backward compatibility if the function is called with 2 arguments, the 
first one is considered as being the layer and the 2nd as the text.


 No need to change the README.