bebop v0.2.1

Changelog:

Several changes for compatibility with upstream, specifically comparing against TypeScript generated code:

• Deprecated message fields are no longer written. They can still be parsed. (https://github.com/RainwayApp/bebop/wiki/Writing-Bops:-The-Bebop-Schema-Language#the-deprecated-attribute)
• Union sizes previously included the discriminator byte. They no longer do. (https://github.com/RainwayApp/bebop/wiki/Wire-format#unions)
• Generated code no longer writes opcodes, they only offer them as values for users to write if they would like to write them. (from misleading graphic: https://github.com/RainwayApp/bebop/wiki/Writing-Bops:-The-Bebop-Schema-Language#opcodes)

There is a remaining failure in compatibility with typescript that is a known problem with the upstream: betwixt-labs/bebop#148

Other Changes:

• When a const exceeds the limits of what can be stored in a variable in Go, instead of erroring out we now offer a warning.