Update materials_overview.adoc

First pass at making table 1 more readable.

src/docs/asciidoc/jme3/advanced/materials_overview.adoc

@@ -47,14 +47,16 @@ jMonkeyEngine supports illuminated and unshaded Material Definitions.
 *  Unshaded materials look more abstract. 
 
 “Unshaded materials look somewhat abstract because they ignore lighting and shading. Unshaded Materials work even if the scene does not include a light source. These Materials can be single-colored or textured. For example, they are used for cards and tiles, for the sky, billboards and UI elements, for toon-style games, or for testing. 
-[cols="3", options="header"]
+[cols="3", options="header", caption=]
+.Material Definition
 |===
 
-a| Standard Unshaded Material Definition 
+a| Standard Unshaded 
 a| Usage 
 <a| Material Parameters  
 
-a| Common/MatDefs/Misc/Unshaded.j3md 
+a| Common/MatDefs/Misc/ +
+Unshaded.j3md 
 a| Standard, non-illuminated Materials. +
 Use this for simple coloring and texturing, glow, and transparency. +
 See also: <<jme3/beginner/hello_material#,Hello Material>>