make rest2html links in README relative

Also update line number to point to rest2html command use.
add tests for rendering .litcoffee as markdown
add .litcoffee to the list of Markdown file extensions
alter test markup/rendered-html files to match better
Note other extensions for AsciiDoc

https://github.com/github/markup/blob/master/lib/github/markups.rb claims to support `markup(:asciidoctor, /asc|adoc|asciidoc/)` so note those extensions here.
Merge pull request #182 from github/relativize_readme

Make links in README relative
rstrip results to avoid errors dealing with newlines at the end of a file
Fix failing tests

All of these deal with attributes moving around in the files.
Add script/bootstrap to get all the required libs
Add cibuild script
More cibuild updates
Properly run easy_install for travis
Use pip for Travis
Add vendor to .gitignore
Fix LHS test file
:lipstick:
Merge pull request #217 from github/fix-tests

Fix tests
Merge pull request #212 from jglick/patch-1

Note other extensions for AsciiDoc
Merge branch 'master' into litcoffee
Convert &gt; to >