Before merging to master

Can you have a look at this pull request? It should go well into your branch and contains teh changes I would merge into master. I repeat some comments, I already added to your pull request. It might mak emopre sense to write here, since your pull request doesn't work straight forward any more due to my changes.

A few questions and notes for you:

- the tree view has some functionalities that do not work yet, right? For example the properties of map, which shows up both on folders and maps, but then doesn't do anything. Are you planning to make those functional? Else we might want to remove them for now?
- I have removed the mapsdirmanager project, since it doesn't make sense in the geopap project folder. Just as heads up
- I renamed a the mapsforge folder to follow the other libraries naming conventions. Doesn't do much, but will have to be reloaded
- the look and feel of the treeview has been modified to reflect the one of geopaparazzi, hope that is ok for you

Think that is all.