SRP 2018.3 Upgrade

I have upgraded the Scriptable Render Pipeline series so it works with Unity 2018.3. There are a few changes.

MyShaderIncludePaths is gone, as that approach is no longer supported. Instead, core library files are included via Packages/com.unity.render-pipelines.core and our own files via a relative include path.

The MyRP folder has been removed. Everything in it has been moved up into My Pipeline.

Updated to core library to version 4.6.0-preview.

The shadow keywords are now declared in const strings.

ConfigureLights and RenderShadows are only invoked if there are any visible lights. When there are no lights, the keywords are disabled, unity_LightIndicesOffsetAndCount is cleared, and PerObjectLightIndices8 is not used. This is needed because otherwise Unity crashes when there are no visible lights.

I also switched the project to use linear light intensity. That's done by setting GraphicsSettings.lightsUseLinearIntensity to true. It's now included in section 2.3 of Lights. To keep the intensity of all lights the same, raise their intensity value to the power of 2.2. You can do that directly in the input field, for example by replacing 7 with 7^2.2.