Fix console command description.
Improve warning print.
EC_WaterPlane: use materialRef instead of materialName + some cleanup while at it, fixes #627. MaterialName still exists and works, but prints a deprecation warning. Add new WaterPlane.material (a copy of Ocean.material) that doesn't have the hardcoded reflection texture of Ocean.material, fixes #630. WaterPlane.material is used as the default material of EC_WaterPlane.