Merge pull request #21 from clintongormley/master

Updated Changes for v0.08
Removed RESOLVING and REJECTING
Deferred's throw an error if resolved/rejected more than once
Rejected handlers which return a value call a chained promise's resolved handler
and callbacks are not required - if they're not code refs they are ignored
Tidied
Fixed version check in skip clause in t/050-exceptions-pp.t