Feature/documentation topic (#822)

- Implement documentation topic that can be used to query documentation using the network API.
- Implement a way to pass arguments to lua scripts using json (rather than formatting entire lua string clientside)
- Implement ability to attach callback to lua script executions
- Implement abillity to transport return values from lua scripts back to network API clients.
- Do not initialize server interface on slave nodes.
- Implement Dictionary -> json converter using nlohmann json library

config/two_nodes.xml

@@ -33,4 +33,9 @@
     <User eyeSeparation="0.065">
         <Pos x="0.0" y="0.0" z="4.0" />
     </User>
-</Cluster>
+</Cluster>
+<!--
+Usage:
+for master: <executable> -local 0
+for slave: <executable> -local 1 --slave
+-->