[[ ssb ]] added serverType property to allow detection of backend.

closes #106

This allows package developers to create branching code to support different SSB server types.

Author: soapdog

src/core/platforms/nodejs-ssb/ssb.js

@@ -152,6 +152,8 @@ const setMsgCache = (id, data) => {
 
 class NodeJsSSB {
   constructor() {
+    this.serverType = "nodejs-ssb"
+
     // add basic built-in pipelines
     pipelines.thread.use(this.filterHasContent)
     pipelines.thread.use(this.filterTypes)