Fix Polynomial's repr to not TypeError when coefficients are Quantities.
Doc-indent-fix and note what rank 0 means.
Corrected and completed documentation of Iterable.cartesian()
Added Vector.pointwise(), clarified documentation of .delta().
Killed some spurious debug, added some documentation.
Another TODO.
Support L&infin; and L2 norms for Vector.

Added squaresum for the L2 norm; and biggest for the index at which the
largest co-ordinate appears.
Reworked .biggest in terms of a generalisation of iteritems().

This makes the traversal more efficient than iterating over keys and
performing a recursive lookup on each.
Fixed implementation of Vector.delta().

It previously only supported integer parameters, though its
documentation spoke of arbitrary index-tuples (of full length) into
tensors.  Revised the doc-string to mention the integer case as an
allowed variant, implemented the previously documented behaviour and
chose what to do about not-exactly-full-length indices.
Implementation of the "find nearest in set" part of Voronoi.
More documentation, options and other refinements for voronoi.Catchment

Replaced the same=True parameter of .nearest() with an elide=()
parameter, for greater generality (at no cost in code complexity; and
it's easier to explain in the doc).  Fixed handling of this (when same
was True, so that ancestors of the box containing where could be empty
if their other leaves are, one of these ancestors could cause the actual
nearest neighbour's box to be eliminated in .__nearleaves()) by setting
.points on all nodes in the BTree, not just the leaves.

Reworked BTree somewhat.  Splitting now prefers to happen on a less
recently used index even if a more recently used one has a smaller
diameter (to avoid bad behaviour if many points lie on some hyperplane
with one coordinate constant).  Added a .parent attribute in support of
that.  Details have shifted around a bit among BTree's private methods
in the process, notably turning its @classmethod .__btree() into a
.__child() instance method.

Made the internal bisection tree private (s/\.tree/.__root/wg).
Let client tune the number of points in each BTree.
Documented the classes and most methods.
Added page-splits in strategic places.
Distinguish the more extreme idiosyncracies and document +1 tests.
List.__getitem__ doc-fix.

Looks like I moved it from Ordered at some ancient point and forgot to
revise the docs to match ...
Use Vector.xerox to get zero vectors, instead of fromSeq.
Generalise Vector diagonal() to arbitrary rank.
Use list comprehensions in Vector in preference to functional tools.

... at least where terser.  In particular, this made the use of
postcompose merely contrived, so I eliminated it.  Added a method
__isnumeric() to simplify various places testing for numbers as opposed
to vectors; also to give coherence to such checks.
Make Vector more amenable to sub-classing.

Replaced fromSeq()'s dimension parameter (which was only used in two
places, in both of which it was used fatuously) with a template from
which to infer which classes to use at each step of collecting values up
into vectors.  Made __repr__ use the name of the actual class in use,
not just assume it hasn't been subclassed.
Added Namely, a Vector with named components.

Also supports various conveniences for clarity.
Minor rephrasing (and reflow) in Vector.embed() doc.
Fixed fiddly conditional to the right way round.

In voronoi.Catchment.__neareleaves()'s check for half of a split being
the new best node, I'd managed to confuse myself by having the if branch
be the "not as good" while the preceding comment's explanation related
to the "at least as good" condition.  So reversed the conditional to
make it take the form of the condition explained - and correct its
conditioning on whether the split node used to be the best.