1.1.1 2016/10/30 BUG

• When Gyoto is configured to be installed in another prefix than
  /usr/local/, look into two additional directories when loading
  plug-ins: /usr/local/lib/gyoto// and
  /usr/local/lib/gyoto/.
• The name of the versioned directories for plug-ins (
  above) is now the major version of the library, so users don't
  need to reinstall there plug-ins when ugrading Gyoto to a
  binary-compatible release.
• --enable-hardening now also enables -fPIE.
• Yorick: actually implement picture' painter for the matte_paint framework. Allow using any two or three-dimensional image or stack of images in the picture' and `panorama' painters.
• Include minimal plug-in example in plugins/null/.