add mocha tests for travis CI integration tests on code commit

squash all commits to single commit
Merge pull request #120 from whiteout-io/mocha

Add travis CI job and mocha tests in phantomjs
Update README.md

Add travis badge to readme
Update README.md

Remove duplicate title
Merge branch 'master' of git://github.com/openpgpjs/openpgpjs
Accept encryption key if subkey signature key flag is null