Both C++ and Python plugins now can implement icon() metadata function which returns path to the icon file name.
The icon file is passed to QPixmap() constructor. For C++ it's preferred to use an icon from the resource file
(e.g. ":/plugins/foo/foo_icon.png") because plugin's resource file gets loaded automatically when the plugin is loaded.
Python plugins can use either relative path to the icon ("images/plugin-icon.png") or icon from the resource file
(starting with a colon). The relative path is preferred, since it doesn't require the plugin to load its resource file
and plugin repository will not have a trouble to fetch the icon automatically.
Updated C++ plugins and Python plugins to include icon where applicable.
Default plugin icon is (c) Anna Shlyapnikova, licensed under Creative Commons (Attribution 3.0 Unported).
git-svn-id: http://svn.osgeo.org/qgis/trunk@14897 c8812cc2-4d05-0410-92ff-de0c093fc19c
