Removed panel2 related configuration.
Added xkb-plugin to top panel.
Added default configuration for xkb-plugin.
Fixed xkb-plugin configuration path.
Merge branch 'xkb-plugin'

* xkb-plugin:
  Fixed xkb-plugin configuration path.
  Added default configuration for xkb-plugin.
  Added xkb-plugin to top panel.
  Removed panel2 related configuration.