face: Implement WebSocket channel, face, and factory.

Change-Id: Ic4dbb1abdbbdbec028746ba14b11be8ab9cc1edb
Refs: #1468
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..0b8f2ee
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "websocketpp"]
+    path = websocketpp
+    url = https://github.com/zaphoyd/websocketpp.git