handle uchar as bytes, not strings in python 3
handle uchar as bytes, not strings in python 3

* This worked in Python2 because bytes and strings are equivilant and the macro
  PYGLIB_PyString_FromStringAndSize evaluated to a PyString
* In Python 3 PYGLIB_PyString_FromStringAndSize evaluates to a PyUnicode
* PYGLIB_PyBytes_FromStringAndSize evaluates to a PyString in Python 2
  and a PyBytes object in Python 3

davidmalcolm/pygobject,jdahlin/pygobject,MathieuDuponchelle/pygobject,jdahlin/pygobject,MathieuDuponchelle/pygobject,thiblahute/pygobject,jdahlin/pygobject,choeger/pygobject-cmake,davibe/pygobject,davidmalcolm/pygobject,davidmalcolm/pygobject,sfeltman/pygobject,nzjrs/pygobject,davibe/pygobject,thiblahute/pygobject,sfeltman/pygobject,nzjrs/pygobject,pexip/pygobject,thiblahute/pygobject,alexef/pygobject,pexip/pygobject,alexef/pygobject,alexef/pygobject,choeger/pygobject-cmake,MathieuDuponchelle/pygobject,davibe/pygobject,GNOME/pygobject,GNOME/pygobject,davibe/pygobject,pexip/pygobject,choeger/pygobject-cmake,GNOME/pygobject,nzjrs/pygobject,sfeltman/pygobject