Fix headers at regex lesson
More reformatting indentation
Fix MATLAB challenges numbering
Merge pull request #768 from r-gaia-cs/fix-matlab-challenges-numbering

Fix MATLAB challenges numbering
Merge pull request #723 from r-gaia-cs/more-fix-at-regex-lessons

More fix at regex lessons
Index for web data tutorial
Merge branch 'master' of github.com:swcarpentry/bc
Added additional challenge to 04-cond to combine conditional, per discussion with @jdblischak
replaced parameter with argument, identified argument with a defualt value of TRUE, and changed name of argument to use_boxplot
Updated new challenge wording to drop boolean and instead refer to the use_boxplot argument
Merge pull request #779 from jhollist/master

Added additional challenge to novice R lesson 04-cond to combine conditional statements.