ViewManager refactor

Hey

I've added the possibility to add viewpages from e.g. plugins.


Now I need some feedback on the API, currently when adding the view page / the page item one needs to specify the "row-text", the icon, etc.. do we want that as interface for the viewpage? Sounds cleaner but would make the viewpage less generic for other programs to use maybe.. dunno, tell me what you like.. also parameter order, I have no preference on that :)