Release 0.1.1rc2

Fixes
-----
- Fix importing of composites #10 
- Add the composites and `roof_duality` to top level namespace

dwave/preprocessing/__init__.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-__version__ = '0.1.1rc1'
+__version__ = '0.1.1rc2'
 
 from dwave.preprocessing import *
 import dwave.preprocessing.composites