Strip comments after further pondering

It turns out that those FIXMEs weren't correct... due to the numeric
nature of the problem being discussed (range and AOE) at some point
there was going to have to be a symbol to value transition and that's
best done as late as possible so as to allow for full rules coverage
and soforth. As a result, trying to do a numeric representation of
CTRL is just silly as it'll get resolved to a numeric through a bunch
of rules anyway.
Fix the buid, add isFAValid

 - Fix a bunch of silly issues that broke the build... grumble grumble
   broken commits

 - Implement isFAValid, a predicate to ensure that a FA count is
   legitimate with regards to list building. Returns `True` for all
   values of a FA such that the FA is not negative, returns `False`
   for (FA $ -1), being the only error case.