SDL clients: Show the probability that a (spy) action will be successful

See patch #4654

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24771 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
civ2civ3 ruleset:
- Removed "OneAttack" flag from land units
- Increased cost of Howitzer

Patch by David Fernandez <bardo>

See patch #4646


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24772 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Set correct size for gui_layer containing activity icons in sdl2-client

See patch #4633


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24775 a0f10bec-cc02-0410-94fc-a9cfff90b4cd