libnl: split libnl into smaller libraries

Some modules may require only libnl-genl, some
libnl-route and fewer would require libnl-nf.

This patch splits the entire libnl package into smaller
more granular libs that can be installed individually as required.

Also added libnl*.so symlinks for convenience.

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>

SVN-Revision: 47037