This patch fixes some things missed in recent commits:
- insert attack sounds into maceman templates (D2855/rP24499 was rebased before D1354/rP24478 was committed)
- let Kushites start with an healer on (most) skirmish maps (D2843/rP24422 added them only to random maps)
- correct fortress tooltips (D1762/rP24393 gave fortresses a territory root, D2801/rP24470 removed champion cavalry and chariots from them)
- Rome siege walls are much narrower and lower than other walls and thus need smaller foundations (not done in D2502/rP23609)
- removed the unused IshtarGate visible class
- move the Ishtar Gate of Babylon out of the pers/ folder; it was built during the Neo-Babylonian Empire, i.e. predating the Persian Empire; Stonehenge isn't in the brit/ folder either (D2472/rP23888 removed it from the building lists)
- rename two unused icons (barracks.png → military.png and ishtar_gate.png → bull.png) to allow D2551 to rename their used counterparts (pers_barracks.png → barracks.png and pers_gate.png → ishtar_gate.png)
- insert placeholder icons in all free and autoresearched technologies that didn't have one already
- insert @Freagarach into the balancing credits