Added new set of material for a R only bootcamp

This material is based on @karthikram's bootcamp that was held in Canberra.
added notes on documentation.
Added notes on documentation addresses issue #112, renumbered sections.
Removed numbering both for sections and exercises within.
started data.table demo
updated data.table demo, added .md file
Add first pass at ignore file information.
Added more ignore material
Update based on feedback from @wking.

- use Git when talking about the command
- fix typo
- unix directory slashes
- line lengths
Updated gitignore material based on feedback to PR 202
Added comments and extra explanation to examples.  Also added .R file with just code
removed generated files
Moved Rmd file to new directory in intermediate/misc/data.table
Fixed some typos, added example of larger file for fread() example
Fixed a typo (oops)
Fixes issue #21

fixes issue #12
Added the messy data file. Fixes #11
Fixes #6
closes #5
closes #4