Bump maps generated by a TSL function

[boytchev]

It is unclear how to make TSL bump map. Maybe this feature is not implemented yet? For example, all node-properties of `MeshLambertNodeMaterial' in r165 are:

• "isNodeMaterial",
• "lightsNode",
• "envNode",
• "aoNode",
• "colorNode",
• "normalNode",
• "opacityNode",
• "backdropNode",
• "backdropAlphaNode",
• "alphaTestNode",
• "positionNode",
• "depthNode",
• "shadowNode",
• "shadowPositionNode",
• "outputNode",
• "fragmentNode",
• "vertexNode",
• "isMeshLambertNodeMaterial"

No bumps in the list. As a result, some of the TSL textures (like concrete) are put to sleep.

However, there is nodes/display/BumpMapNode.js, so maybe there is a way to have TSL bump maps.