Fix typos in novice Python lessons
Converting to triple-tildes in Markdown source files
Fixing formatting glitch in one Markdown file
Switching to triple-tilde in Markdown code blocks in IPython Notebooks
Merge pull request #205 from ethanwhite/typo-fix

Fix typos in novice Python lessons
Merge pull request #212 from gvwilson/use-triple-tilde-for-code-blocks

Use triple tilde for code blocks
Typo fix: "on" -> "one".
Merge pull request #213 from goxberry/rules-typo

Typo fix: "on" -> "one".
guide-shell/man: rudimentary man lesson

This commit includes work from David Worth.
ENH Add challenges