Let the translator decide where to put the action probability

The spy action button label text of the Qt and the Gtk clients include the
probability of success. Start inserting it as a formatted string so
translators can decide its location via positional specifiers. This is
useful for languages that read right to left.

See bug #21766

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24643 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
AI: Check that a city isn't immune to a spy action because of action enablers

when thinking about targeting it.

See patch #4587

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24644 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Renamed music tag "music_start" as "music_menu"

See patch #4575


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24645 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Make sure gtk3-client does not push out frames quicker than they get drawn.

See patch #4590


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24646 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Split international traderoute types to different types depending on
diplomatic relations between the nations.

See patch #4499


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24649 a0f10bec-cc02-0410-94fc-a9cfff90b4cd