Minor doc updates: FlexBuffers C#, Discord, CppUsage.

Change-Id: Ie34ff580eb2f41ff35f85271b10865f4a14d0dca

docs/source/CppUsage.md

@@ -114,7 +114,7 @@ To use:
     MonsterT monsterobj;
 
     // Deserialize from buffer into object.
-    UnPackTo(&monsterobj, flatbuffer);
+    GetMonster(flatbuffer)->UnPackTo(&monsterobj);
 
     // Update object directly like a C++ class instance.
     cout << monsterobj->name;  // This is now a std::string!
@@ -122,7 +122,7 @@ To use:
 
     // Serialize into new flatbuffer.
     FlatBufferBuilder fbb;
-    Pack(fbb, &monsterobj);
+    fbb.Finish(Monster::Pack(fbb, &monsterobj));
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 The following attributes are specific to the object-based API code generation:

docs/source/FlatBuffers.md

@@ -163,6 +163,7 @@ sections provide a more in-depth usage guide.
 -   [GitHub repository](http://github.com/google/flatbuffers)
 -   [Landing page](http://google.github.io/flatbuffers)
 -   [FlatBuffers Google Group](https://groups.google.com/forum/#!forum/flatbuffers)
+-   [Discord](https://discord.gg/6qgKs3R) and [Gitter](https://gitter.im/lobster_programming_language/community) chat.
 -   [FlatBuffers Issues Tracker](http://github.com/google/flatbuffers/issues)
 -   Independent implementations & tools:
     - [FlatCC](https://github.com/dvidelabs/flatcc) Alternative FlatBuffers
@@ -178,3 +179,6 @@ sections provide a more in-depth usage guide.
     - [FlatBuffers in Android](http://frogermcs.github.io/flatbuffers-in-android-introdution/)
     - [Parsing JSON to FlatBuffers in Java](http://frogermcs.github.io/json-parsing-with-flatbuffers-in-android/)
     - [FlatBuffers in Unity](http://exiin.com/blog/flatbuffers-for-unity-sample-code/)
+    - [FlexBuffers C#](https://github.com/mzaks/FlexBuffers-CSharp) and
+      [article](https://medium.com/@icex33/flexbuffers-for-unity3d-4d1ab5c53fbe?)
+      on its use.

readme.md

 ![logo](http://google.github.io/flatbuffers/fpl_logo_small.png) FlatBuffers
 ===========
 
+[![Build Status](https://travis-ci.org/google/flatbuffers.svg?branch=master)](https://travis-ci.org/google/flatbuffers)
+[![Build status](https://ci.appveyor.com/api/projects/status/yg5idd2fnusv1n10?svg=true)](https://ci.appveyor.com/project/gwvo/flatbuffers)
 [![Join the chat at https://gitter.im/google/flatbuffers](https://badges.gitter.im/google/flatbuffers.svg)](https://gitter.im/google/flatbuffers?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
-[![Build Status](https://travis-ci.org/google/flatbuffers.svg?branch=master)](https://travis-ci.org/google/flatbuffers) [![Build status](https://ci.appveyor.com/api/projects/status/yg5idd2fnusv1n10?svg=true)](https://ci.appveyor.com/project/gwvo/flatbuffers)
+[![Discord Chat](https://img.shields.io/discord/656202785926152206.svg)](https:///discord.gg/6qgKs3R)
+[![Twitter Follow](https://img.shields.io/twitter/follow/wvo.svg?style=social)](https://twitter.com/wvo)
+
 
 **FlatBuffers** is a cross platform serialization library architected for
 maximum memory efficiency. It allows you to directly access serialized data without parsing/unpacking it first, while still having great forwards/backwards compatibility.