mpictor/StepClassLibrary — pull request #178 by davyw (2012-04-09 18:47:24+00:00)
Title: Review/sdai fix exports

This branch fixes build errors on msvc introduced in aggr_runtime_bounds branch.

Import/export macro scheme for sdai libraries is fixed.

@mpictor, @brlcad
I had to change SDAI_Select::operator= in stepcore library from virtual abstract to virtual in order to
fix a number of linker errors. This solves the linker error, but I don't understand why it would be needed
since derived classes do implement SDAI_Select& operator=(const SDAI_Select&).
Any alternative solution is much appreciated...