Merge pull request #3 from knocte/master

Gst.Object: fix property setter
dllconfig: Fix dllnames for GstBase and GstAudio
dllmap: Fix GstVideo library name
dllmap: Fix dllnames for GstPbUtils
metadata: Mark GstBaseSrc as non abstract but not instantiable from managed
Adapter: Add some manually bound methods
Adapter: make it public
metadata: fix more MissingIntPtrCtorException cases

This workaround is getting a bit out of hand...