v0.5.0

Added CLI options.

This adds:

-r, --raw      output the raw rendered value without formatting
-p, --pretty   pretty print the output
-y, --yaml     output as YAML instead of JSON
-h, --help     print this help message
-v, --version  print the version number
--             stop parsing options

And removes:

- `%v`
- `%R`
- `%Y`
- `%J`

Also the Rust library exposes more functions, each for different
formatting options.