You can't use names for the bitwise operators that conflict with the names for Boolean operators (or, and, not). The semi-official (Logo) names are
bitand
bitor
bitnot
ashift (arithmetic, shifts the sign bit down)
lshift (logical, doesn't)
I think these should actually be primitive but not strongly I guess.
I don't think convert to binary belongs in this library. Integers in Snap! are already in binary, even if they don't look like it. I take it your block reports a string of digit characters, and that's not what you give a bitwise operator as input. And also, it's such a great programming exercise to write...