Merge pull request #42 from gvwilson/tidying-up-wording

Further tidy-up based on email feedback.
Minor Addition - Note about Ruby Version.
Merge pull request #47 from agngrant/gh-pages

Minor Addition - Note about Ruby Version.
Reformatting a paragraph
Merge branch 'gh-pages' of github.com:swcarpentry/workshop-template into tidying-up-wording
Tidying up wording of Ruby version note