Adds Google+-optimized publishing size to list of Picasa Web Albums publishing sizes. Closes #5210.
Adds Google+-optimized publishing size to list of Picasa Web Albums publishing sizes. Closes #5210.

h4ck3rm1k3/shotwell,Sanva/shotwell-gsoc,jimbonator/shotwell,h4ck3rm1k3/shotwell,ritchiewilson/shotwell,damianmoore/shotwell,ritchiewilson/shotwell,damianmoore/shotwell,polymeris/shotwell,ritchiewilson/shotwell,jimbonator/shotwell,polymeris/shotwell,Sanva/shotwell-gsoc,jimbonator/shotwell,abrauchli/shotwell,abrauchli/shotwell,polymeris/shotwell,abrauchli/shotwell,damianmoore/shotwell,Sanva/shotwell-gsoc,h4ck3rm1k3/shotwell