Extend duckling to understand financial market time

[dyladan]

The NYSE market opens at 9:30 and closes at 4:00 on weekdays, however it closes for US holidays. It would be nice if Duckling were able to parse datetime phrases like the following:

• "remind me blah at market open tomorrow" => tomorrow 9:30am
• "what was blah stock at market open today" => today 9:30am
• "schedule blah during market time tomorrow" => tomorrow 9:30am to 4:00pm

I would gladly do the work to make the pull request for at least the english version if someone would point me towards the correct place to do this. If exceptions for holidays are difficult I don't think it would be any problem if they are just ignored.