added back some basic imports into __init__

mhcflurry/__init__.py

@@ -11,3 +11,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+from .class1_binding_predictor import Class1BindingPredictor
+from .predict import predict