Dear colleagues!

As a step towards the implementation of long axonal delay support in NEST by Jan (https://github.com/nest/nest-simulator/pull/2989), Jan has prepared and I have recently merged https://github.com/nest/nest-simulator/pull/3947, which sorts out the rather unsystematic use of the nest namespace in C++ files. Where we earlier frequently used 

      void nest::iaf_psc_alpha::update(...)

we now wrap the entire file in the namespace and define all methods inside

namespace nest 

{

      void iaf_psc_alpha::update(...)

}