#44 Better slash_hit_parade validation

[Phil Ringnalda]

slash:hit_parade needs better validation than just
text(), but it's not clear whether it's just "a string
of comma-separated integers" as the spec says, or
actually "a string of seven comma-separated integers
without spaces, the first being equal to
slash:comments" as it experimentally seems to be.

Is that ^(\d)+(,(\s)*(\d)*)*$ maybe?