libopac: Use UTF-8 the WebOpacAtTest was failing for me on Windows otherwise
libopac: Use UTF-8
the WebOpacAtTest was failing for me on Windows otherwise

thesebas/opacclient,simon04/opacclient,opacapp/opacclient,johan12345/opacclient,raphaelm/opacclient,thesebas/opacclient,raphaelm/opacclient,ruediger-w/opacclient,ruediger-w/opacclient,opacapp/opacclient,opacapp/opacclient,geomcmaster/opacclient,raphaelm/opacclient,thesebas/opacclient,johan12345/opacclient,simon04/opacclient,johan12345/opacclient,geomcmaster/opacclient,simon04/opacclient,geomcmaster/opacclient,johan12345/opacclient,opacapp/opacclient,opacapp/opacclient,ruediger-w/opacclient,johan12345/opacclient,ruediger-w/opacclient,ruediger-w/opacclient