Importing shell lesson for novices
Fixing title (needs to be H1, not H2)
Example files for intro to shell
Merge branch 'master' into new-shell-beginner-lessons
Fixing headers and image links
First draft of glossary
Tidying up shell lesson
Merge branch 'master' into new-shell-beginner-lessons
Merge pull request #162 from gvwilson/master

Master
Merge branch 'master' into new-shell-beginner-lessons
Merge pull request #139 from gvwilson/new-shell-beginner-lessons

New shell beginner lessons