update to new github pages version
better docs for private dependencies and encrypting files, move to separate pages, rework pro docs, enable syntax highlighting
Merge branch 'gh-pages' into rkh-sshkey-and-encrypt-file
API docs: add fingerprint to public key
API docs: add maximum_number_of_builds
API docs: Environment Variables
API docs: SSH keys
regenerate API docs
API docs: add TravisPy
Merge pull request #96 from travis-ci/rkh-sshkey-and-encrypt-file

improve documentation for private dependencies and encrypting files