Encapsulate ordering and naming conventions in separate classes. (#273)

The end goal here is to be able to more clearly separate which bits of `Layout` are specific to the algebra, and which are specific to the choice of blade names and numbers.

This changes the signature of the `Layout` function.
It's likely no one was using it, but just in case we support the old signature and emit a deprecation warning.

clifford/__init__.py

@@ -28,6 +28,17 @@
     Layout
     ConformalLayout
 
+Advanced algebra configuration
+------------------------------
+It is unlikely you will need these features, but they remain as a better
+spelling for features which have always been in ``clifford``.
+
+.. autosummary::
+    :toctree: generated/
+
+    BasisBladeOrder
+    BasisVectorIds
+
 Global configuration functions
 ==============================
 These functions are used to change the global behavior of ``clifford``.
@@ -304,6 +315,7 @@ def val_get_right_gmt_matrix(mt: sparse.COO, x):
 from ._layout import Layout  # noqa: E402
 from ._multivector import MultiVector  # noqa: E402
 from ._conformal_layout import ConformalLayout  # noqa: E402
+from ._layout_helpers import BasisVectorIds, BasisBladeOrder  # noqa: F401
 from ._mvarray import MVArray, array  # noqa: F401
 from ._frame import Frame  # noqa: F401
 from ._blademap import BladeMap  # noqa: F401

clifford/_conformal_layout.py

@@ -51,7 +51,10 @@ def __init__(self, *args, layout=None, **kwargs):
     def _from_base_layout(cls, layout, added_sig=[1, -1], **kwargs) -> 'ConformalLayout':
         """ helper to implement :func:`clifford.conformalize` """
         sig_c = list(layout.sig) + added_sig
-        return cls._from_sig(sig=sig_c, firstIdx=layout.firstIdx, layout=layout, **kwargs)
+        return cls(
+            sig_c,
+            ids=layout._basis_vector_ids.augmented_with(len(added_sig)),
+            layout=layout, **kwargs)
 
     # some convenience functions
     def up(self, x: MultiVector) -> MultiVector: