capacitor2d template: now uses an automatic segment seed point algorithm
finalized device generator template example (including comments)
device class now offers a description string

this can be used by, for instance, a device template generator
to forward the meta-information to the actual device object
major overhaul of device class, carrying now the  project description

moved the ViennaFVM::project_description into the device class,
same variant approach as with the viennagrid::mesh.

the device now assigns the doping via the viennafvm mechanism,
also the epsr is automatically assigned as soon as a material is assigned
to a segment.

-> the problem implementation (laplace, poisson_dd-np) are now much simpler,
as they require the presence of, e.g., the permitivity in the project description.

-> this approach is now similar to ViennaSHE approach

all examples work
broken device generator: updated device generator due to ViennaMesh update +

however, device generator doesn't work atm as ViennaMesh API information is missing
-> waiting for proper example in ViennaMesh