Improve the docs a bit for foreground dispatch.

     * <p>This will give give priority to the foreground activity when

     * dispatching a discovered {@link Tag} to an application.

     *

     * <p>Activities must call {@link #disableForegroundDispatch} in

     * their {@link Activity#onPause} callback.

     *

     * <p>a null set of intent filters will cause the forground activity

     * to receive all tags.

     *

     * <p>This method must be called from the main thread, and

     * only when the activity is in the foreground (resumed).     *

     * <p>If any IntentFilters are provided to this method they are used to match dispatch Intents

     * for both the {@link NfcAdapter#ACTION_NDEF_DISCOVERED} and

     * {@link NfcAdapter#ACTION_TAG_DISCOVERED}. Since {@link NfcAdapter#ACTION_TECH_DISCOVERED}

     * relies on meta data outside of the IntentFilter matching for that dispatch Intent is handled

     * by passing in the tech lists separately. Each first level entry in the tech list represents

     * an array of technologies that must all be present to match. If any of the first level sets

     * match then the dispatch is routed through the given PendingIntent. In other words, the second

     * level is ANDed together and the first level entries are ORed together.

     *

     * <p>If you pass {@code null} for both the {@code filters} and {@code techLists} parameters

     * that acts a wild card and will cause the foreground activity to receive all tags via the

     * {@link NfcAdapter#ACTION_TAG_DISCOVERED} intent.

     *

     * <p>This method must be called from the main thread, and only when the activity is in the

     * foreground (resumed). Also, activities must call {@link #disableForegroundDispatch} before

     * the completion of their {@link Activity#onPause} callback to disable foreground dispatch

     * after it has been enabled.

     *

     * @param activity the Activity to dispatch to

     * @param intent the PendingIntent to start for the dispatch

     * @param filters the IntentFilters to override dispatching for, or null to always dispatch

     * @param techLists the tech lists used to perform matching for dispatching of the

     *      {@link NfcAdapter#ACTION_TECH_DISCOVERED} intent

     * @throws IllegalStateException if the Activity is not currently in the foreground

     */

    public void enableForegroundDispatch(Activity activity, PendingIntent intent,