fix minor wording errors describing SSL certificate updates
update links to Homebrew in warning and error messages
Merge pull request #2865 from bmichelsen/osx-ssl-certs-text

fix minor wording errors describing SSL certificate updates
escape the test keyword to avoid aliases, fix #2867
Merge branch 'master' of github.com:wayneeseguin/rvm
escape all head and tail occurences, update #2861
command head for scipping functions and aliases, fix #2861
Merge pull request #2866 from bmichelsen/osx-homebrew-link

Update Homebrew links on OS X
Update Homebrew repo location, also helps fix #2866