The main reason why I'm adding this isn't actually to allow
users to swipe down to refresh, it's to add a loading indicator.
Considering that the Storage Access Framework can be slow for
folders with many items (many subfolders?), not showing a
loading indicator might give users the impression that adding
a folder resulted in nothing happening even though Dolphin is
scanning for games in the background. But I suppose letting
users swipe down to refresh is a nice bonus with the change.

Whenever the EmulationActivity crashes and the app gets back to the
TvMainActivity, dolphin will crash tring to restor the mBrowseFragment
since we don't save the adapter data in the bundle.

This is quick hack to avoid the crash. The proper fix would be to save the
adapter data in the bundle and restore it before restoring the fragment
when the activity gets recreated.

Crash Stacktrace:
Process: org.dolphinemu.dolphinemu.debug, PID: 30353
java.lang.RuntimeException: Unable to start activity ComponentInfo{org.dolphinemu.dolphinemu.debug/org.dolphinemu.dolphinemu.ui.main.TvMainActivity}: java.lang.IllegalArgumentException: Invalid position 1 requested
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2691)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2752)
    at android.app.ActivityThread.-wrap12(ActivityThread.java)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1461)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6120)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
    Caused by: java.lang.IllegalArgumentException: Invalid position 1 requested
    at android.support.v17.leanback.app.BrowseFragment.createMainFragment(BrowseFragment.java:509)
    at android.support.v17.leanback.app.BrowseFragment.replaceMainFragment(BrowseFragment.java:1454)
    at android.support.v17.leanback.app.BrowseFragment.setAdapter(BrowseFragment.java:764)
    at org.dolphinemu.dolphinemu.ui.main.TvMainActivity.buildRowsAdapter(TvMainActivity.java:183)
    at org.dolphinemu.dolphinemu.ui.main.TvMainActivity.onCreate(TvMainActivity.java:59)
    at android.app.Activity.performCreate(Activity.java:6664)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2644)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2752) 
    at android.app.ActivityThread.-wrap12(ActivityThread.java) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1461) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:154) 
    at android.app.ActivityThread.main(ActivityThread.java:6120) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)