Fix enum handling for comparisons and casts

• e8f6835: Add handling for bit shifting with lower precision types
• db12274: Add support for correctly casting Enums to integer types. I'm not sure if it's possible to go the other direction from int to enum with what Udon currently exposes. Reported by @synergiance
• 2244bfe: Add handling for comparing enums using Object.Equals internally since Udon does not yet expose comparison operators for enum types, reported by @synergiance