Shorter type error messages

[RunDevelopment]

Changes:

• Type comparisons (e.g. The type X is not connectable with type Y.) are now shorter. If X or Y is a struct and the other is either an incompatible struct or a primitive type, then all struct fields will be omitted. This makes error messages with structs shorter and easier to understand because it removes a lot of noise.
• Pretty print types. I added a function to pretty print types. While it currently just replaces some int intervals with "int" or "uint", we might want to add more to this later.

(Note how all fields of the image type are omitted.)