Update CHANGELOG format
Add gitignore
Add generic Makefile
Add Travis CI
Refactor envconsul to use Consul Template libraries

This commit is rather large, but there is no easy way to split it into
smaller pieces.
Update README with new goodies
Make CHANGELOG format the same as other projects
envconsul all lowercase
Simplify Runner Wait()
Do not test tip
Merge pull request #22 from hashicorp/sethvargo/tuneup

Give envconsul some TLC ;)