Add context back
Add sign as separate value to support -0 and +0
Assert that rounding preservs sign for -0
Fix more -0 issues
Print -0 with sign
Add NaN, Infinity and spec errors
Test special values
Add flags and traps to context
Raise on sNaN, silent on qNaN
Add overview and context docs and some typespecs

Also adds the "up" rounding strategy and renames "half_away_from_zero"
to "half_down".
Return correct operand for min and max when numerically equivalent
Moar docs
More docs about special values and spec