Changed the low battery warning to 16 percent

Due to what I think is an AOSP bug, when the battery reaches the
specified amount (previously
15 percent) it warns the user when it reaches one minus that level.
For example, if it is configured to show at 15 percent, it now shows at
14 percent.
There is no major concern with this issue--and I would have left it at
showing
14 percent--but 14 is such a freaking weird number.

Signed-off-by: htchoi1995 <htchoi1995@gmail.com>