Significantly decreased CPU usage.

Calls to InputStream#available() weren't blocking, so the loops
in both classes were running hot. Replaced the conditional with
a blocking call instead. CPU usage is down from 100% to barely
noticable.

android/src/main/scala/com/nutomic/ensichat/bluetooth/BluetoothTransferThread.scala

@@ -65,12 +65,13 @@ class BluetoothTransferThread(context: Context, device: Device, socket: Bluetoot
 
     while (socket.isConnected) {
       try {
-        if (inStream.available() > 0) {
-          val msg = Message.read(inStream)
+        // Block until data arrives.
+        inStream.read(Array[Byte](), 0, 0)
 
-          onReceive(msg, device.id)
-          Log.v(Tag, "Receiving " + msg)
-        }
+        val msg = Message.read(inStream)
+        Log.v(Tag, "Received " + msg)
+
+        onReceive(msg, device.id)
       } catch {
         case e @ (_: ReadMessageException | _: IOException) =>
           Log.w(Tag, "Failed to read incoming message", e)

core/src/main/scala/com/nutomic/ensichat/core/internet/InternetConnectionThread.scala

@@ -50,11 +50,13 @@ class InternetConnectionThread(socket: Socket, crypto: Crypto, onDisconnected: (
     try {
       socket.setKeepAlive(true)
       while (socket.isConnected) {
-          if (inStream.available() > 0) {
-            val msg = Message.read(inStream)
+        // Block until data arrives.
+        inStream.read(Array[Byte](), 0, 0)
 
-            onReceive(msg, this)
-          }
+        val msg = Message.read(inStream)
+        Log.v(Tag, "Received " + msg)
+
+        onReceive(msg, this)
       }
     } catch {
       case e @ (_: ReadMessageException | _: IOException) =>