Tiny nomenclature nits in SIA V2 spec

[Tom McGlynn (NASA/GSFC Code 660.1)]

Reading the spec today I was initially confused by a couple of 
references to 'open or closed intervals' in parameter selections (e.g., 
in 2.1.2 and 2.1.3) which to me naively is a statement about whether the 
end points are included.   What was intended here was surely the
'open-ended' interval -- where one of the limits is +/- infinity used 
elsewhere in the spec and almost but not quite defined in 2.1.

There's also a bit of confusing text in 2.1: "If  the lower or upper 
bound is not specified, the range is open-ended."  but in  2.1.2 we see that
    BAND=-Inf 0.21
is open-ended while
    BAND=0.21
which drops one of the bounds is not an interval at all, but rather a 
constraint  on the minima and maxiuma of the data if: b_min<= 0.21 and 
b_max>=0.21
which seems a bit inconsistent.

Nothing big here, but briefly confusing.

     Tom McGlynn