New map: London - Paris

Changes in this version:

• New track added (London - Paris)
• Minor changes on the previous track (Vienna - Budapest)
• We have a really simple main menu from now
• Optimized game loading speed
• When rail selector popup is active, you can see direction arrows around stations. These are showing you the possible connection slots. 
• A lot of improvements in the calculation of the number of passengers and station efficiency
• Skybox minor adjustments
• Water material fixes

IMPORTANT: Previous save games are not compatible with this version!