Remove encrypted SMS transport, simplify transport options.

Closes #2647

// FREEBIE

src/org/thoughtcrime/securesms/TransportOptionsPopup.java

@@ -0,0 +1,73 @@
+package org.thoughtcrime.securesms;
+
+import android.content.Context;
+import android.graphics.drawable.BitmapDrawable;
+import android.support.annotation.NonNull;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewTreeObserver;
+import android.view.WindowManager;
+import android.widget.AdapterView;
+import android.widget.ListView;
+import android.widget.PopupWindow;
+
+import java.util.LinkedList;
+import java.util.List;
+
+public class TransportOptionsPopup implements ListView.OnItemClickListener {
+
+  private final TransportOptionsAdapter adapter;
+  private final PopupWindow             popupWindow;
+  private final SelectedListener        listener;
+
+  public TransportOptionsPopup(@NonNull Context context, @NonNull SelectedListener listener) {
+    this.listener = listener;
+    this.adapter  = new TransportOptionsAdapter(context, new LinkedList<TransportOption>());
+
+    View     selectionMenu = LayoutInflater.from(context).inflate(R.layout.transport_selection, null);
+    ListView listView      = (ListView) selectionMenu.findViewById(R.id.transport_selection_list);
+
+
+    listView.setAdapter(adapter);
+
+    this.popupWindow = new PopupWindow(selectionMenu);
+    this.popupWindow.setFocusable(true);
+    this.popupWindow.setBackgroundDrawable(new BitmapDrawable(context.getResources(), ""));
+    this.popupWindow.setOutsideTouchable(true);
+    this.popupWindow.setWindowLayoutMode(0, WindowManager.LayoutParams.WRAP_CONTENT);
+    this.popupWindow.setWidth(context.getResources().getDimensionPixelSize(R.dimen.transport_selection_popup_width));
+
+    listView.setOnItemClickListener(this);
+  }
+
+  public void display(Context context, final View parent, List<TransportOption> enabledTransports) {
+    this.adapter.setEnabledTransports(enabledTransports);
+    this.adapter.notifyDataSetChanged();
+
+    final int xoff = context.getResources().getDimensionPixelOffset(R.dimen.transport_selection_popup_xoff);
+    final int yoff = context.getResources().getDimensionPixelOffset(R.dimen.transport_selection_popup_yoff);
+
+    popupWindow.showAsDropDown(parent, xoff, yoff);
+
+    parent.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
+      @Override
+      public void onGlobalLayout() {
+        popupWindow.update(parent, xoff, yoff, -1, -1);
+      }
+    });
+  }
+
+  public void dismiss() {
+    this.popupWindow.dismiss();
+  }
+
+  @Override
+  public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
+    listener.onSelected((TransportOption)adapter.getItem(position));
+  }
+
+  public interface SelectedListener {
+    public void onSelected(TransportOption option);
+  }
+
+}