Importing old lesson from Version 4 on regular expressions as a starting point for new work.
Add CSS for printing

The CSS was add at our main CSS and remove from printing:

- Logo at header
- GitHub ribbon
- Footnote

Close #561.
convert START-HERE.html to START-HERE.md

Markdown conversion using PANDOC
Shrink the font size for print version
Split markdown out into separate files
Delete START-HERE files
Change text tables to diagrams, add png files
update tabs and spaces description
typo
Merge pull request #564 from danmaclean/creating-lesson-on-regular-expressions

Creating lesson on regular expressions
Merge pull request #562 from r-gaia-cs/media-print

Add CSS for printing