Cargo + rust-nightly + no need for feature(globs) + fixed travis-ci config

First off, sorry for the long pull request, I know it's hard to inspect.
I discovered rust recently and wanted to try it out replacing a module of a working project, as an experiment. Protobuf is a requirement and I found this amazing project, however it stopped working when I updated to the nightly rust, I also wanted to be able to specify it as a dependency with Cargo.
So, I've been doing some changes to adapt this lib to a functional state from my point of view, and I think this changes will be appreciated by all users of this lib.

This pull request should close #29, make this lib usable with latest rust as seen on the travis-ci, eliminates the need for the user to enable feature(globs) on their crate and fixes .travis.yml to use the latest rust and cargo.

Again, sorry for the long list of features on a single pull request, I hope you have time to merge it.