script: do not open script buffer when unknown arguments are given to command /script
relay: add tag "relay_client" in all messages about client
Merge branch 'master' of git://git.sv.gnu.org/weechat
relay: fix crash after /upgrade when a client is connected
irc: fix crash when splitting a message with tags
irc: add tags "irc_nick1_xxx" and "irc_nick2_yyy" in message displayed for command "NICK"
relay: add backlog, options and server capability "server-time" for irc protocol (task #12076)

New options:
- relay.irc.backlog_max_minutes
- relay.irc.backlog_max_number
- relay.irc.backlog_since_last_disconnect
- relay.irc.backlog_tags
- relay.irc.backlog_time_format
core: fix detection of command in input: a single command char is considered as a command (API function "string_input_for_bufer")
core: fix memory leak in case of error when building content of bar item for display
irc: fix memory leak when updating modes of channel
irc: remove unneeded check of nick pointer (can not be NULL there)
relay: fix memory leak when adding hdata to a message (weechat protocol)
script: add missing close of file in case of error when computing MD5 checksum of a file
xfer: fix memory leak when refreshing xfer buffer
Version 0.4.0-rc1
core: update copyright dates
core: fix scroll in buffer after enabling/disabling some filters (if scroll is on a hidden line) (bug #37885)
core: fix scroll to bottom of window (default key: alt+end) when line displayed is bigger than chat area
doc: update german translations, FAQ, scripting and user guide
relay: send UTC time in irc backlog (when server capability "server-time" is enabled)