Fix some potential bugs

Correct some of the issues found with coverity scan. Things like
an unused pointer, variables that could potentially be used in an
uninitialized state, a copy-paste error, and a couple spots where
the return value wasn't checked.
I18n: Update translation id (80%).

173 translated messages, 43 untranslated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
Fix some more potential bugs

An unchecked return value, unintended sign extensions, and a copy
paste error.
I18n: Update translation id (99%).

215 translated messages, 1 untranslated message.

Transifex (https://www.transifex.com/projects/p/xfce/).
Refresh desktop on style changes

Xfdestkop's icon view doesn't update the icon labels when xfsettingsd
starts up. To work around that, refresh the desktop on a style change
event. Additionally gtk likes to send up to 10 style change events at
once, so this also adds a 1 second delay to ensure it's the last change
event that we respond to.
I18n: Update translation id (100%).

216 translated messages.

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

216 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
Fix issues with icon resizing
I18n: Update translation is (100%).

216 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).