1.6 Release

This update adds quality of life features,  a level-up system and various fixes.

• Reduced file size
• Upgrades don't increase maintenance anymore
• New level system: services progress from level 1 to 5, this determines the strength of the upgrades that can be inserted
• New "Information" visualization that displays helpful tooltips ("view" window)
• Selecting/removing now works according to the displayed layers ("view" window)
• Condition decreases are better randomly distributed now
• Build/area tools now allow making the area smaller again
• The stock market is now less profitable
• Day of season is now displayed.
• Fixed a bug concerning customers walking out of screen
• Fixed a bug concerning upgrading staff
• Various fixes for the GUI
• Balancing changes