360° panorama helper plugins

This plugin set contain 4 plugins helpful in 360° equirectangular panorama
creation:

• fill_zenith_nadir - fills transparent areas on the top and the bottom of
  the generated panorama with a gradient that smoothly connects to the
  neighbor pixels
• panorama_to_zenith_nadir - converts panorama to editable form of zenith
  and nadir areas. This allows for easy editing, eg. patching, filling,
  placing a logo
• zenith_nadir_to_panorama - converts back the editable zenith and nadir to
  panorama projection
• set_google_plus_metadata - attach metadata needed to publish panorama on
  Google+

Plugin homepage: http://sourceforge.net/p/gimp360panorama/wiki/Home/