core: Add support for static libraries to include other whole static libs.

Currently, if LOCAL_WHOLE_STATIC_LIBRARIES is specified, its values is
ignored. This patch addresses this limitation and works as follows:
For every whole lib specified, it extracts the archive into a sub-directory
under the target lib's intermediate, and then seeds the initial target
archive with all the members.

Signed-off-by: Dima Zavin <dima@android.com>