Moved all csv files into new "data" subdirectory
Updated paths in lessons 01 to 04 to account for data files being moved to 'data' subdirectory. Created *.md files using 'knit' in RStudio.
Copied python example coding images from bc/novice/python/img and
updated *.Rmd and *.md files to reference new image location.
Updated html files for lessons 01 - 04 by running 'make preview' using
*.md files with fixed path to data files
Replaced argument "pat" with "path" in list.files call
Merge pull request #4 from mlammens/gh-pages

Move data files to 'data' subdirectory and change references to these files in lessons files