An experimental tool for pruning a proto tree into a smaller subset for compilation by other tools.
Arguments: --in=dir --out=dir [--includes=pattern] [--excludes=pattern] [file]
Patterns must be in one of the following formats:
* Partial package name followed by a `*` (e.g., `com.example.*`).
* Full package name of a type or service.
* Full package name, a `#`, and the name of a member.
Multiple patterns can be supplied to a single argument by separating them by
a `,` (e.g., `--include=com.example.*,com.other.package.*`).
File must contain patterns prefixed with either `+` or `-` to signify an include
or exclude, respectively. All other lines are ignored.