Add a11y setting for Automatically click after pointer stops

Adds new preference screen for the feature, where the feature can be
enabled/disabled, and delay before click can be specified (implemented
as seek bar preference, enabled iff the feature is enabled).

Preference is added to Accessibility setting. The preference summary is
set to string describing the delay after pointer stops moving before
click is scheduled (the string also contains numerical value of the
delay).

BUG=20049245

Change-Id: Ib7b2f5c24efbd08e3200143c069bcdbc9b5a327a

src/com/android/settings/InstrumentedFragment.java

@@ -26,6 +26,8 @@ public abstract class InstrumentedFragment extends PreferenceFragment {
     // Declare new temporary categories here, starting after this value.
     public static final int UNDECLARED = 100000;
 
+    public static final int ACCESSIBILITY_TOGGLE_AUTOCLICK = UNDECLARED + 1;
+
     /**
      * Declare the view of this category.
      *