Multiple versions of the same library can't be used in the same
project because even tho project take care to include from
the right vectorwrapper-1.0/ dir the inclusion guard is the
same. So in spite of having a different path and livingi in a
different namespace, ifndef is preventing the inclusions to work.
This is useful when vwr is used and publicly exposed in a
library. If both the library and the standalone project depend
on vwr, this change gives the user the opportunity to keep the
two usages separate. This is especially important if both the
library and the standalone program happen to specialize the
Info template for the same type.
King_DuckZ