Fix reversed logic in dai_is_unit_tired_waiting_boat

See patch #4839

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@25270 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Use gen-move compatible bodyguard filter

Add caching of relevant unit_class and unit_type checks

See patch #4649

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@25271 a0f10bec-cc02-0410-94fc-a9cfff90b4cd