Env cubemap

Env cubemap's are used for cheap reflektion, in order of it to work env_cubemaps must be placed threw out the map, after the map has been compiled the mapper needes to type in buildcubemaps in the console in order to generate the textures that will be used for the reflection, the textures will be generated relative to the placement of the env_cubemaps. Materials using env cubemap's will use the texture's generated for the env_cubemap entity nearest to them.