GitLab

* adapted corresponding classes
* adapted build system

* moved libeep to ext
* adapted all classes
* adapted build system

test accordingly

maipulators home position now as soon as the first element of the scene has
been added. This improves the rotation center and space bar behavior. It
maybe fixes #216 (please check this)

[CHANGE] - teem now gets found in /opt/teem too and the CMakeFiles now properly handle other paths (others than /usr/ and /usr/local)

[CHANGE] pressing a ctrl key while picking an object with the mouse ignores the first picked object, this lets the user pick something behind nav slices for instance

[CHANGE] - renamed export defines to sound a little bit less Windows-specific (and therefore make this visual studio specific evil sound a little bit less evil)

[CHANGE] - our build system now supports module toolboxes. All our current modules where sorted into one of the toolboxes. The file modules-user.toolbox is not versioned and can be used for user defined lists of modules.