Pathfinding miscellaneous fix in pf_fuel_map_iterate():
* The function doesn't return a tile twice anymore.
* The previous cost of a path is now calculated from the fuel_segment values.
* Removed pq_delete().
* Added pq_replace() to prevent tile index to be listed many times in priority
queues.

From a report by Marko Lindqvist (cazfi@gna)

See gna bug #21523

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24280 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Set the movement cost for a UTYF_IGTER unit disembarking with slow_invasions
disabled to MOVE_COST_IGTER, like in previous versions of Freeciv.

See gna bug #21535

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24285 a0f10bec-cc02-0410-94fc-a9cfff90b4cd