Added a lesson on making packages in R.
Updates based on suggestions by jdblischak
Updates based on suggestions by jdblischak
Merge branch 'master' of https://github.com/jainsley/bc
Small edits to lesson on creating R packages.
switching flag order for jekyll
Added novice reference page on recognising shell, Python and editors within a shell window and how to exit from these
1.  Modifying home page validator to make sure that the contact address *isn't* 'admin@software-carpentry.org'.
2.  Adding tests for validator's checking of helpers list.
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
Making instructions for checking bootcamp home pages more prominent
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
Improve "Recognising prompts" section

- Add images
- "How to exit" right after the images.