Game version 0.95.117 released

Notable changes:

• Balance: reduced Garthog force strength on Mission 5: Escort Admiral Tullen for easy and normal players. [Issue #691]
• Admiral Tullen's battleship should now show up with 100% health, although its hitpoints are far less than the regular Thorin.
• Added Spy Center graphics and is buildable, although not doing anything and AI is ignoring it.