chore: remove babel, fix integration tests

This commit removes babel/es6 from all source and test files, because it was introducing a lot of overhead and only little gain.
This commit fixes and enables integration tests on Travis.
This commit fixes #153 and #151 along the way.

_Originally this commit should have only removed babel, but without working tests that's a bit too hairy._
_I only realized that half way into removing babel/es6, so things are all over the place now._

Closes #153, Closes #151

.gitignore

@@ -1,14 +1,9 @@
-# common
 coverage
 node_modules
 test/registry/couch
 test/registry/data
+test/tmp
 *.log
 *.dump
 .DS_Store
 .nyc_output
-.test
-.tmp
-
-# build-artifacts
-dist