updating debugging slides
updating debugging slides
unit testing material
update unit testing
update unit testing
more exercises
more exercises
solutions to exercies
remove solutions
Reshuffling content a bit
remove solutions
also add html output
describe the problems
update Rtools and mention knitr
Forgot to add read.R
Update the pdf
cite unittesting source
Merge commit 'f6c323012f5aa5edd05c33177548289a10567fc0'
Merge commit '54d7a2772f2d684ccb760a61b8cec8f3ee0917ea'