Fix autoconf checks for building panel plugins
Fix compile error in battery panel plugin
Fix LXDE plugin build error
Tweaks for the settings dialog
Improve strings in devices tab and add percentage (Bug #6652)
Only show menu separator when there's items to separate

In the battery plugin, there's a chance that we've filtered out
any devices to display and thus there's no need for the menu
separator.
I18n: Update translation hr (100%).

209 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation pt_BR (87%).

183 translated messages, 26 untranslated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation zh_TW (100%).

209 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation en_AU (100%).

209 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation de (100%).

209 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation fr (100%).

209 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation bg (100%).

209 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation nl (100%).

209 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation pt (100%).

209 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation ja (100%).

209 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation uk (97%).

204 translated messages, 5 untranslated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation nb (98%).

205 translated messages, 4 untranslated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
Settings dialog: Align table columns in size groups
Increase glade project minimum required gtk+ version to 2.16

...so it stops complaining.