A Debian branch to test arangodb - the image is 115MB smaller than the ubuntu image

Hi, 
This shouldn't be merged into master but could be a branch to create a debian image. 
As seen with the image stats, its less than 200MB, while the ubuntu image is 315MB. With my internet connection this makes a difference :)

```
arangodb            latest              420b93085974        2 days ago          315.4 MB
pmario/adb          latest              5780ce614b8e        2 days ago          198.9 MB
```

-----------

I'm not sure if the local install setting works. There is no documentation, why the `libicu52_52.1-3_amd64.deb` is needed for the local install. 

```
# install from local source
if test "$local" = "yes"; then
 dpkg -i /install/libicu52_52.1-3_amd64.deb
 dpkg -i /install/arangodb_2.2.3_amd64.deb
```