--warning (clang3.2)
closes #76
@Trophime, @cdaversin and @StephaneVeys, this was an interesting bug in fact
it may actually be a clang bug. clang was considering that an enum was a
double or at least not an integer type. It was detected only for 3D code since
the enum was present only in 3D whereas in 2D and 1D it(nDim) is defined as an
uint16_type. Now GeoElement3D defines nDim as a uint16_type.
The problem was always there :)