Use WeakReferenes to reduce Bitmap memory footprint

Use HashMap<Integer, WeakReference<Drawable>> instead of just
    HashMap<Integer, Drawable>

Without this, references are still being held for Bitmap drawables,
thereby after few Photo edits, OutOfMemoryException is raised and
Gallery crashes

Conflicts:
	src/com/android/gallery3d/filtershow/filters/ImageFilterBorder.java

Change-Id: If91f950986bd816d5571a0d51a7cb9522226e270
Gallery2: Fix menu bar layout display error in portrait mode

The forward button is interlock with separate line.

Modify layout param to make the layout display normal.

CRs-fixed: 674514

Change-Id: Idf09aee09c67ad943109ad054fe8d4bfa41e4061