tests: add tests of functions string_shared_get and string_shared_free
relay: disable SSLv3 by default

The new default value for option relay.network.ssl_priorities is now
"NORMAL:-VERS-SSL3.0".
irc: disable SSLv3 by default in server option "ssl_priorities" (closes #248)
irc: use option irc.look.nick_mode_empty to display nick prefix in bar item "input_prompt"
doc: add "beep" trigger in question about highlights (FAQ)
core: add bar item "mouse_status", new options weechat.look.item_mouse_status and weechat.color.status_mouse
core: update translations
core: update ChangeLog
core: update German translations
python: remove comment added by mistake
doc: update German auto-generated files