Update notes for v1.0.6

[p]Truck City v1.0.6 has just been released. This changelog also includes changes made in v1.0.5 and v1.0.4:[/p]

• [p]Balance: Curionian Spit: some items can't be bought anymore; patch v1.0.3 increased the inital amout of money, which may enable the player to rush to research just buying everything and completely ignoring city building.[/p]
• [p]Bugfix: regression bug introduced in v1.0.3 corrected, where research would not correctly start.[/p]
• [p]Bugfix: corrected bug which caused science window to become impossible to close if inspecting the full dependency graph after clicking on a container icon, then used right click to close the full dependency graph.[/p]
• [p]Bugfix: Leaderboard button in main menu is now disabled until the boards are loaded. Prevents a bug where only partially loaded leaderboards would be shown[/p]