Bugfix patch v0.5.1

This update has some minor bug fixes and improvements. Mostly related to the trade routes from the previous update.

The changelog for the v0.5.1 update:

• Fix rendering of trade route lines in release builds
• Fix potential exceptions when removing trade stops
• Include Robots in the population panel
• Use icons for the buttons on the cargo ship panel
• Improve pacing of some of the introduction storylets