Adds the glumb visualizer as git submodules to the repository (#123)

.gitmodules

+[submodule "IOTAtangle"]
+	path = IOTAtangle
+	url = https://github.com/glumb/IOTAtangle.git
+[submodule "socket.io-client"]
+	path = socket.io-client
+	url = https://github.com/socketio/socket.io-client.git

IOTAtangle @ 07bba77a

+Subproject commit 07bba77a296a2d06277cdae56aa963abeeb5f66e

socket.io-client @ 661f1e7f

+Subproject commit 661f1e7fac2488b6d3d206f96bb59073c4c98b1c