Unpack content of .aar bundle and copy to current dist dir.

def _unpack_aar(self, aar, arch):
        '''Unpack content of .aar bundle and copy to current dist dir.'''
        with temp_directory() as temp_dir:
            name = splitext(basename(aar))[0]
            jar_name = name + '.jar'
            info("unpack {} aar".format(name))
            debug("  from {}".format(aar))
            debug("  to {}".format(temp_dir))
            shprint(sh.unzip, '-o', aar, '-d', temp_dir)

            jar_src = join(temp_dir, 'classes.jar')
            jar_tgt = join('libs', jar_name)
            debug("copy {} jar".format(name))
            debug("  from {}".format(jar_src))
            debug("  to {}".format(jar_tgt))
            ensure_dir('libs')
            shprint(sh.cp, '-a', jar_src, jar_tgt)

            so_src_dir = join(temp_dir, 'jni', arch.arch)
            so_tgt_dir = join('libs', arch.arch)
            debug("copy {} .so".format(name))
            debug("  from {}".format(so_src_dir))
            debug("  to {}".format(so_tgt_dir))
            ensure_dir(so_tgt_dir)
            so_files = glob.glob(join(so_src_dir, '*.so'))
            for f in so_files:
                shprint(sh.cp, '-a', f, so_tgt_dir)