KlayGE: Samples: Fix the compiling issue in EnvLighting

KlayGE: Samples: Fix the compiling issue in EnvLighting

KlayGE: Bump up the version to 4.17.0

KlayGE: Rendering: Enable to load a RenderMaterial without a valid Re…

…nderFactory

External: Updated openal-soft

KlayGE: Octree: Fix some issues in OCTree SceneManager

1. In OCTree::*Visible, the variable visible was bool before, so if (visible) is right. But it was changed to BoundOverlap type, it's wrong (just opposite) to use if (visible),
2. Add missing OCTree::FrustumVisible,
3. Call parent class's *Visible in OCTree::*Visible, instead of copying code.

Engineering: Find git executable before using it (Github #203)

Doc: Update the version number

Doc: Update the version in readme

KlayGE: DR: Fix the scan based ClusteredDRLightIntersectionCS on sm 5.1.