Added introduction to writing command-line programs with R.
Added objectives to writing command-line programs with R.
Added section that demonstrates how to run a file with Rscript as well as use commandArgs.
Added first two examples of reading inflammation data from the command line.
Added exercise on creating command line program to do addition and substraction.
Added challenge on creating command-line program to find all files with a given pattern.
Added section on Handling Multiple Files from the command-line.
Switched file endings from .py to .R
Added challenge to check dimensions of multiple files.
Added section on Handling Command-Line Flags.
Added challenges on command-line flags.
Added section on Handling Standard Input.
Added Challenge on creating a program like Unix wc.
Added key points to lesson on command-line programs.
Small edits to comand-line programs in R.
Switched from print to cat to properly write values to standard output, one per line.
Added more info about pausing and killing R processes.
Merge branch '06-cmdline' of github.com:jdblischak/bc into lessons
Merge branch 'lessons' into gh-pages