Re-introducing unit testing
Adding link back in instructions
Added pandas slides
Added exercises to Pandas notebook
Added solutions to pandas notebook
Added pandas slides
shell-filedir notebook directory reorganization

* removed redundant instructor notebook
* renamed shell-overview more appropriately to shell-filedir
Suggested revisions to PR #93

Very minor editing and fixes
Example files for intro to shell
Merge branch 'gh-pages'
Merge branch 'master' into new-shell-beginner-lessons
Fixing headers and image links
First draft of glossary
Segregated exercise solutions to separate file
Moved pandas files into misc-pandas
removed html rendering of older version of the lesson
Rewriting material on testing
Fixed two broken links in lessons/index, one in a lesson
Merge pull request #100 from HaveF/reorg_images

PR: Reorganize images
Merge pull request #155 from wltrimbl/fixlinks

Fixed broken links