Add some newly introduced source files to our MSVC project (gtk2_ardour)
Add some newly introduced source files to our MSVC project (libpbd)
class 'PBD::Configuration' doesn't actually get exported from libpbd - so make sure we don't decorate it with LIBPBD_API
Remove the source files which got transferred to libpbd
Some of libardour's istream and ostream operators are needed outside of libardour - so let's make them exportable

(currently, only the istream operators are needed but we might as well do them both)