Added Lg_Floor() to bitwise ops (tentatively keeping Lg_PowerOf2() on the grounds that it's SLIGHTLY faster, but in the end probably not enough to make a difference), also replaced innards of AuxPowersOf2 with frexp() / ldexp() since, when BitOp is available, band() does not play well once the input gets to 32 bits and up... now slightly slower then, but faster when emulated (though again, nothing huge); I may need to sit down and better plan out how to make this module more consistent, and maybe divide it up (especially if I start adding things in earnest)