Add makefile & enable more regular contribution from rightscale/rlog back to brsc/rlog

Hi Bram; I hope you're well.

RightScale has a fork of rlog, but it had diverged significantly from your upstream. We need to "work ahead" and add features that make sense to us, but I also want to be capable of contributing improvements back to you.

I took some time today to rewrite history on our fork so it has a clean merge base with brsc/rlog. This pull request makes two changes:
- renames all packages and internal imports to "rightscale/rlog" (so we can cleanly use our fork)
- adds a Makefile with the interface that you implemented while working at RightScale, with a few improvements

Obviously you should not accept the commit that renames "brsc" to "rightscale!" However, you can merge the pull request by hand and discard the changes where brsc gets renamed. Once you commit your merge, the offending commit from rightscale/rlog will never again be merged, your packages and imports will continue to be named "brsc," and future PRs from us to you should merge more cleanly.

Let me know if this style of collaboration makes sense to you. We have a few other improvements we'd like to contribute upstream, but I thought we should figure out how to deal with the package-naming issue first.