When trying all 3 of these libraries together (just adding them
with e.g. `derelict-gl3` so latest version) I get:
```
C:\Users\fruit\OneDrive\Desktop\MathProjects\DerelictTest\derelicttest2>dub
generate visuald
Error Unresolvable dependencies to package derelict-util:
derelict-gl3 1.0.24 depends on derelict-util >=1.0.3
derelict-glfw3 3.1.3 depends on derelict-util ~>2.0.4
derelicttest2 ~master depends on derelict-util ~>2.1.0
```
Not sure what it means, or how to fix without spending too much
time trying out all the 1000's of possible combinations of
package versions.
So any hints?
