Importing old lesson from Version 4 on regular expressions as a starting point for new work.
convert START-HERE.html to START-HERE.md

Markdown conversion using PANDOC
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