hugo ex/sim reorganize

hugo/content/ex/sim/depthprobe/_index.md

 +++
 title = "Depth probe"
-weight = 0
+weight = 80
 +++
 
 ## Depth probe examples

hugo/content/ex/sim/offspec.md

 +++
 title = "Off-specular"
-weight = 30
+weight = 20
 +++
 
 ## Baisc off-specular scattering example

hugo/content/ex/sim/scatter2d/_index.md

++++
+title = "Scattering in 2d"
+weight = 30
++++
+
+## Script examples: scattering in 2d
+
+{{% children %}}