add workers_only mode for zmq server where workers can be started on remote machines and attach to current running server
add a :worker_port option for backend of zmq broker and no longer editing the port/options as it is passed through runner/server/broker/worker
add specs for workers_only/worker_port and PB_WORKERS_ONLY through ENV
add register_signals to each server runner and TTIN to zmq to start new workers
documentation update
add logger methods to runner
bump to 2.7.3
update broker in zmq to wait to open the frontend socket to take in requests until workers are ready
bump to 2.7.4
have zmq workers die or kill them after 5 seconds
add ! method to get raw value from protobuf message
bump to 2.7.5
Compile Extension Fields to correct message class

The libprotoc Generator provides extension fields
to a FileDescriptor or Descriptor object. I
misunderstood that the descriptor extension fields
are not the fields that belong to the corresponding
message proto/class.

The fix is to store the extension fields by their
containing type name when we initially parse
through the messages in the file descriptor.
Then when we  go to print each message's fields
we print out the previously extracted
extension fields.

Fixes #69.
Ignore value assignment on unknown fields
Merge pull request #75 from localshred/stable_fix_extensions

Compile Extension Fields to correct message class
Merge pull request #76 from localshred/stable_fix_message_ext_field_init

Ignore value assignment on unknown fields
Bump version 2.7.6
Merge branch '2-7-stable'