Move the libraries into separate packages.

Creates the following additional packages: libzpool2, libnvpair1, libuutil1 and libzfs2.

Talk in Debian GNU/Linux concluded that there is no point in separating libzfs and libzfs_core. They are so dependent on each other that there is no/little point/requirement to have them separated. So <code>libzfs_core.so.1</code> is in the <code>libzfs2</code> package.

Visual inspection have shown everything is a-ok. Currently trying out the patch on a Fedora20.

Closes: #2329