* add `make help` target
* remove unused variables
* add .exe to the binary name when on windows
* add ldflags to go build to strip the binary (smaller binary size)
* `make protos` must be executed manually when proto files change
The doc.go file in the proto package allows protobuild to find all protobuf
packages in the project and compile the protos.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>