By default they are on, but you can disable them by adding the
following configuration value:
[params.sharingicons]
hide = true
If this parameter is undefined (or "false") then the icons will be
shown. Furthermore, you can disable specific icons by setting their
value to "false", ie:
[params.sharingicons]
facebook = false
Any icons not named will be shown. Currently there a four icons
configureg: facebook, googleplus, linkedin, and twitter.