appveyor: install requirements after installing wheel
appveyor: install requirements after installing wheel

Former-commit-id: 27244b4fd56d31bd9211332b4002f247ed6e0889
sylvanmist/worldengine,MM1nd/worldengine,esampson/worldengine,esampson/worldengine,psi29a/worldengine,psi29a/worldengine,sylvanmist/worldengine,Mindwerks/worldengine,tmfoltz/worldengine,Mindwerks/worldengine,MM1nd/worldengine,tmfoltz/worldengine