CLI arg refactor, cleanup, various bugfixes

Fairly significant cleanup release; significant refactor (moved to a diff lib); cleanup of some flags.

Support for GCP PubSub

Added support for GCP PubSub.

Decompression + Default Exchange

• Added support to gzip decompress output on reads (from kafka and rabbit)
• Removed --exchange-name as required arg (forgot that rabbit has default exchange support)

Initial release

This is the initial release of the port of our internal "plumber" tool that we use for consuming and publishing messages on our event bus.

It is nowhere near feature complete, but it does have the most important part implemented (in our opinion):

It is able to read and write protobuf based messages to either Kafka or RabbitMQ. We think that's pretty damn sweet.

We hope it's useful for you!