Add option for optional/no space internally between one-or-more number repeats

[bskinn]

Would be useful for the GAMESS hessian; possibly other cases.

Probably put it as an optional flag after the quantity flag but before the sign flag: #!+x.f

Putting it before the quantity flag would run the risk of an ambiguous non-capturing token: the x of #x+.f could be either for space-after or for internal-space.

Or, could use different, non-colliding flag characters... but for intuition's sake they should probably be the same.

Could potentially restrict this to only be allowed for the floats/scinots with a specified number of digits past the decimal (#66), because for integers there's not as much of an intrinsic 'digits-past-anything' semantics to them?