CRAN fix

[richfitz]

Required to fix duplicated vignette index title: work currently on branch develop

• [ ] check with r-hub that solaris checks now pass (check they used to fail?)
• [x] check with r-hub that darwin checks now pass (ditto?)
• [x] check with win builder that duplicated vignette title is fixed
• [x] prepare tarball with r-release

[richfitz]

Submitted as 0.9.1 see tag: https://github.com/richfitz/stevedore/releases/tag/v0.9.1