Some tests for overflow
longSplitBits added
More testing added for splitBits

standard splitBits can only handle numbers up to 2^53-1, use
longSplitBits for larger values
bitwise And modified to handle signed bits

and tested!
bitwise Or now also handles sign bits

and tested!
bitwise XOR now handles signed bits

and tested!
all bitwise shifts tested with longer bit strings

all tests pass!