[BUG #7512] correcting JS operators
[BUG #7512] properly handle ints in hex (and octal) formats

- so hex constants can be used in reductions
- add util.parseInt() for this
- add a reduction rule for <group> nodes (so "(3) & 4" is evaluated)
- add more operands for less frequent JS operations (bit ops, shift ops)
- guard against self.operations lookups with unknown operations
minor re-format
[BUG #7512] fall back to simpler solution for righ-shift ops

- after testing the simple solution for RSH works (although in theory it shouldn't)
- while the elaborate solution doesn't (although it should)