Develop js

@scriptedSheep or @irruputuncu or @FraBle  or @Lixissimus:
Sorry for being so late with my pullrequest, but I needed to wait for finishing your first merge between develop and develop-js. I fixed all the bugs I found. Even if I reviewed this filse carefully, I don't want to push them without pullrequest on the develop branch, as I am introducing some model extensions concerning issues #40, #41 from sprint 3. Would be nice, if anyone could have a look on it before merging.