Added notice that setting takes effect next turn to phasemode help.

See bug #21631


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24486 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Added lua function tile:has_road()

See patch #4497


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24489 a0f10bec-cc02-0410-94fc-a9cfff90b4cd