Request proper tail/tail bud development term in GO

[seger]

From Malcolm, originally in #26:

In the case of the tail/tail bud I couldn't find a [GO] development term, only morphogenesis. As Josh has said above these are distinct concepts so 'post-anal tail morphogensis' probably shouldn't be in this table [of developmental terms we would like to see incorporated initially] and we should be lobbying GO to add a proper development term.