Merge pull request #137 from latot/topo_intro

Minor fixes

Author: robe2

postgis-intro/sources/en/topology/components.png

@@ -29,18 +29,19 @@ Layers are the biggest box, they store TopoGeometries which also stores TopoElem
 
 Just to write in two ways:
 
-- Layer contains
+* Layer contains
 
-  - TopoGeometries where each one one contains
-  - TopoElements where each one can represent a
+  * TopoGeometries where all of them has the same TopoElement's type, each one one contains:
 
-	- TopoGeometry of other Layer
-	- Primitive from the Topology
+    * TopoElements where each one can represent a:
 
-  	- Nodes
-  	- Edges
-  	- Faces
-  	- Geometry Collections
+	        * TopoGeometry of other Layer
+        	* Geometry Collection
+	        * Primitive from the Topology
+
+                	* Nodes
+                	* Edges
+                	* Faces
 
 TopoGeometries are exposed as keys, they has a unique key inside the Layer, but also stores its Layer Key, this allows Postgis to store it in an arbitrary column and always be able to find its TopoElements, and with them what they represent.