Bitwise operators and floor division operator from Lua 5.3

[R-033]

Adds support for bitwise operators &, |, ~ (XOR and NOT), << and >>, as well as // from Lua 5.3.

As I understand main reason why these were not implemented in Moonsharp was because it doesn't have an integer type, however I still find these operators useful for running some scripts targeting Lua 5.3. Some other people might find this change valuable as well.