Fixed doc typos in Kernel and String
Bump to v0.12.1-dev
Merge pull request #1938 from jwarwick/doc_typos

Fixed doc typos in Kernel and String
Run tests against erlang R16B03
Merge pull request #1940 from vanstee/travis-r16b03

Run tests against erlang R16B03
Revert "Merge pull request #1940 from vanstee/travis-r16b03"

Travis does not support R16B03 yet.
Ignore build artifacts in _build folders.