Add an initial .travis.yml.

Since kilium is now public, setup travis to verify it.  Thus add an initial
.travis.yml file.  Notably, it uses coveralls to keep an eye on test coverage,
and falls back to normal go testing if the coveralls token is unavailable.  IT
uses an external script due to limitations of travis.
Due to a breaking change in goriakpbc, lock its code to an older revision.

Commit 1ed4ed5f0da94d52dcd019e13183bcb3e27271c6 in goriakpbc broke kilium.
Thus lock the previous revision in travis so that it build sucessfully there.