Add TestOverlay README

Builds/VisualStudio2012/RippleD.vcxproj

@@ -2102,6 +2102,7 @@
     <None Include="..\..\README.md" />
     <None Include="..\..\SConstruct" />
     <None Include="..\..\src\ripple\peerfinder\README.md" />
+    <None Include="..\..\src\ripple\testoverlay\README.md" />
     <None Include="..\QtCreator\rippled.pro" />
   </ItemGroup>
   <ItemGroup>

Builds/VisualStudio2012/RippleD.vcxproj.filters

@@ -2407,6 +2407,9 @@
     <None Include="..\..\src\ripple\peerfinder\README.md">
       <Filter>[1] Ripple\peerfinder</Filter>
     </None>
+    <None Include="..\..\src\ripple\testoverlay\README.md">
+      <Filter>[1] Ripple\testoverlay</Filter>
+    </None>
   </ItemGroup>
   <ItemGroup>
     <Text Include="..\..\doc\todo\NIKB_TODO.txt">

src/ripple/testoverlay/README.md

@@ -0,0 +1,17 @@
+# TestOverlay
+
+This provides a set of template classes for simulating a peer to peer
+network. These facilities are provided:
+
+- Initial construction of the network.
+- Message passing between peers
+- Network wide state information.
+- Per-peer state information.
+
+## Description
+
+Through the use of suitable template arguments, the logic and state information
+for each peer can be customized. Messages are packets of arbitrary size with
+template-parameter defined data. The network is modeled discretely; The time
+evolution of the network is defined by successive steps where messages are
+always delivered reliably on the next step after which they are sent.