* Discuss representation error versus loss of significance.
* Document special values including qNaN, sNaN, +0, -0.
* Show the suprising display of non-normalized zero values.
* Rename "trap_enablers" to just "traps".
* Simplify names of "settraps" and "setflags" to just "traps" and "flags".
* Show "capitals" in the context representation
* Simplify the Context constructor to match its repr form so that only
the set flags and traps need to be listed.
* Representation can now be run through eval().
Improve the error message when the Decimal constructor is given a float.
The test suite no longer needs a duplicate reset_flags method.
* Map conditions to related signals.
* Make contexts unhashable.
* Eliminate used "default" attribute in exception definitions.
* Eliminate the _filterfunc in favor of a straight list.
Docs:
* Eliminate documented references to conditions that are not signals.
* Eliminate parenthetical notes such as "1/0 --> Inf" which are no
longer true with the new defaults.
Facundo Batista
Edward Loper
Raymond Hettinger
Andrew M. Kuchling