Various lint error fixes.

> Fixing some RTL errors by specifying both marginStart and marginLeft
> Moving all layout direction checks to Utilities
> Explicitely adding @TargetApi before every method

Change-Id: Ibe9c52b93b5a6adeadb27ace2b312770fd732ea0

src/com/android/launcher3/MemoryTracker.java

@@ -101,7 +101,7 @@ public class MemoryTracker extends Service {
 
     public void startTrackingProcess(int pid, String name, long start) {
         synchronized (mLock) {
-            final Long lpid = new Long(pid);
+            final Long lpid = Long.valueOf(pid);
 
             if (mPids.contains(lpid)) return;