Support for NewGRF v8
The question is, do we want to support it uncondtionally or do we want to make it conditionally, e.g. by a newgrf-version field within the grf block:
+ old and current stable OpenTTD versions don't support grf v8
+ OpenGFX would need to change its minimum version requirements which
- it's more code and worse maintenance
We probably don't want to consider support for newgrf v8 before 0.2 anyway.