README.md: add alt text to ropensci footer image
README.md: More detail in alt text for build status icons
bump version to 0.5.7
README.md: add alt text to ropensci footer image
README.md: More detail in alt text for build status icons
bump version to 0.5.7
Fix conflict in README.md
Merge pull request #22 from kbroman/master

README: Add alt text for rOpenSci image