Remove space between avatar and user name

The avatar should be shown immediately after the avatar to be able to
accurately define the space between them using only CSS rules.

Note that in the case of the "atwho" menu it is not really needed, as a
whitespace removal seems to be done automatically by the plugin, but it
was modified for its displayed elements too for consistency.

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>