[feature request] Compile bitwise operators into Lua BitOp functions calls

For Lua versions below 5.3, bitwise operators aren't supported. However, their behavior can be substituted using the Lua BitOp library. This library is also included by default with LuaJIT. My suggestion would be to add a boolean argument to the compiler, perhaps a --use-bit-lib (which is what Fennel also uses). In practice, it could compile the code:

bit_or = (x, y) ->
    x | y

into this:

_bitop_0 = require("bit")
local bit_or
bit_or = function(x, y)
    return _bitop_0.bor(x, y)
end

No files or tests are named. Start by locating the compiler handling of bitwise operators and how compiler options are defined; determine how a --use-bit-lib option should affect generated Lua and verify that the example compiles to Lua BitOp calls while normal compilation remains unchanged.