[osis-core] Alpha attached, needs two regexes - Milestonable is not mixed.

[Todd Tillinghast]

Patrick,

Milestonable or the things newly derived from Milestonable should be
mixed.  At present <q>some text</q> is not valid as are a number of
other cases.

I like the pattern of creating an "interface" and deriving from it.  A
word of caution, if we were to consider the numerous other "interfaces"
logically present in the schema we might find that there are other
"interfaces" that would prove more strategic than Milestonable.
(Because schema does not support "multiple inheritance" you only get to
choose one "interface" to extend from.

Todd