FastScroller: Fix to use appropriate index

Fix FastScroller to use appropriate index to determine the
the position of a section while calculating the y coordinates
of thumb. In case of last section, use totalItemCount to determine
next section position.

Change-Id: I89bfd483949b5c14f85303b50380a73b4a4e635e
Fix typo in AlertController.java

If whichButtons is BIT_BUTTON_NEGATIVE, the negative button should be centered.

Change-Id: Ia34daf8c80704204a4f1cf71c642114005559d5d
Signed-off-by: Sangkyu Lee <sk82.lee@lge.com>