Performs a bitwise left shift operation.
shl(value, shift)
shl(1, 3); // returns 8 (0001 << 3 = 1000)
shl(2, 2); // returns 8 (0010 << 2 = 1000)
shl(5, 1); // returns 10 (0101 << 1 = 1010)
bit not and or xor nand nor xnor shl shr