Error: Unexpected token: "XXX.proto". Expected ";"

We do not support `import public` when running `grpc-dynamic-gateway`.

After removing the `public`, it runs without any problem.

```
/home/huan/git/grpc-dynamic-gateway/node_modules/protocol-buffers-schema/parse.js:501
if (tokens[0] !== ';') throw new Error('Unexpected token: ' + tokens[0] + '. Expected ";"')
^

Error: Unexpected token: "puppet/base.proto". Expected ";"
```

Related issue: https://github.com/grpc-ecosystem/grpc-gateway/issues/139

Reproduce the failure in grpc-dynamic-gateway using an import public statement, then inspect node_modules/protocol-buffers-schema/parse.js at the reported parser check. Done means grpc-dynamic-gateway runs successfully without removing public from the import.

Written by the indexing model from the issue text.