v0.3.0-alpha.2: automated release testing (3)

v0.3.0-alpha.1: automated release testing (2)

v0.3.0-alpha.0: automated release testing

v0.2.6: new: `rel_error`, `sign`, `copy_sign` (`abs` as method).

Also, bigger and better docs, and some internal reorganization.

v0.2.5 - totalOrder comparison predicate

This adds `total_cmp`, for doing the IEEE754 `totalOrder` predicate.

Version 0.2.3: #[no_std] and bug fixes.

This release makes the library (unconditionally) #[no_std] compatible,
with no change to the API or functionality.

It also fixes #1 and #6, and tests #5 much better.