Revert "Handle both bzipped and non-bzipped data in DataUnpacker"

This reverts commit 05d3970e39.

app/assets/javascripts/player/data_unpacker.js.coffee

@@ -1,14 +1,11 @@
 class AsciiIo.DataUnpacker
   unpack: (base64BzippedData, callback) ->
-    data = atob base64BzippedData
+    bzippedData = atob base64BzippedData
 
-    if data[0] == 'B' and data[1] == 'Z'
-      if window.Worker
-        worker = new Worker(window.unpackWorkerPath)
-        worker.onmessage = (event) => callback event.data
-        worker.postMessage data
-      else
-        data = ArchUtils.bz2.decode data
-        callback data
+    if window.Worker
+      worker = new Worker(window.unpackWorkerPath)
+      worker.onmessage = (event) => callback event.data
+      worker.postMessage bzippedData
     else
-      data
+      data = ArchUtils.bz2.decode bzippedData
+      callback data