Enable Rubinius 2.x builds, make Rubinius optional
Formatting, fast finish
Merge branch 'master' into optional-ci-builds

Conflicts:
	.travis.yml
Fix VM hostname
Skip re-installing slapd et al
Setup retcode overlay

Useful for testing out specific server responses in integration tests
Revert re-install guard, debugging
Revert revert re-install guard
Add return code integration tests
Merge pull request #130 from ruby-ldap/optional-ci-builds

Move Rubinius (1.9, 2.x) to monitored but unsupported (optional, allowed failure) build
Merge pull request #132 from ruby-ldap/openldap-ci-retcode

[CI] Wire up retcode OpenLDAP overlay for testing specific server responses
Merge branch 'master' into instrument-messages