lowered cmake minimum version because of appveyor
lowered cmake minimum version because of appveyor

gamedevforks/LumixEngine,JakubLukas/LumixEngine,zhouxh1023/LumixEngine,dreamsxin/LuxEngine,galek/LumixEngine,JakubLukas/LumixEngine,galek/LumixEngine,gamedevforks/LumixEngine,zhouxh1023/LumixEngine,dreamsxin/LuxEngine,JakubLukas/LumixEngine