time package - parsing of incorrect data

[Paolo Losi]

Ashley Yakeley wrote:
> Possibly it should use instead "validating constructors" that return a 
> Maybe type. 

I'm totally in favour of "validating constructors", also for Day values
(as an alternative to silent truncation).

I guess it would also be useful to differentiate between strict parsing
errors (wrong format of the data) and unvalid fields (hour > 24).

Ashley, please let me know if you need some "code monkey" help.

Thanks
Paolo