Really fix yawn

This does what d959ba1 failed to do. We always need to consider whether
the year we're jumping to is a leap year or not.

Really fixes #87.
Example files.
Add an argument to the test app.
Merge pull request #93 from mrdomino/date-bug

Really fix yawn
Change :tach to :chat, ^V to ^D.
Sends a friendly change warning.
Lengthen timer to 30s.  Highly suspect.
Really long timerz.
Duh.
Don't put empty directories in unix-built ankh.
Ye olde trailing whitespace cleanup

Done via:

    find urb/zod -type f | xargs sed -i 's/\s\+$//'

And subsequently glanced at before committing. The only thing that caught
my eye is that hoon.hoon:7496 is now a blank line.