Numpoly

==========================

FIXED:
* truncate function affected by rounding error.

==========================

ADDED:
* Numpy function addition: `det` (from `np.linalg`).

==========================

ADDED:
* Numpy function addition: `roots`.

==========================

ADDED:
* Functions `remove_redundant_coefficients` and
`remove_redundant_names` to explicitly remove junk information.
* Global flags `retain_coefficients` and `retain_names` to set global
defaults.

CHANGED:
* Post-process with `postprocess_attribute` mandatory for all calls to
`clean_attributes`, but because of the new flags, keeping polynomial
unchanged is still possible.

REMOVED:
* Flag `clean` arg replaced with more explicit `retain_coefficients` and
`retain_names`.

==========================

CHANGED:
* The call signature of `numpoly.call` changed to make its usage different
from `__call__`.
* the call signature of `numpoly.monomial` change to make it more aligned
with its parent `numpoly.glexindex`.

==========================

ADDED:
* Numpy function additions: `one_like`, `zeros_like`.

CHANGED:
* Enforce 100 percent coverage in CI.