RF: add top-level module imports for all modules

Fixes gh-13.

transforms3d/__init__.py

@@ -8,6 +8,11 @@
 from . import taitbryan
 from . import affines
 from . import quaternions
+from . import euler
+from . import axangles
+from . import reflections
+from . import shears
+from . import zooms
 
 from ._version import get_versions
 __version__ = get_versions()['version']