Update README

The previous version said that one of the three things it did was to "provide a few lenses only included in recent augeas releases".
The module doesn't do that anymore, and some of the other things it did do were not document, so this updates the README to be more current.
Merge pull request #21 from micah/patch-1

Update README
Rename README as README.markdown
Use markdown in README
Add augeas() function
Add .travis.yml
Update README
Add Modulefile
Improve README
Do not escape _ in README
Reorganize classes
Fix augeas::lens with new module organization
Use defined instead of declared
Add Gemfile
Fix ::params::pkgs as ::params::augeas_pkgs
Abstract package name for ruby-augeas, define dependency for all Augeas
resources
Improve rspec options
Add specs for hosts
Fix augeas::lens
Fix .fixtures.yml