SML+WEB: update link to cosmo2013
WEB+SML: update requirements for exercises
WEB+SML: add examples of measures
WEB+SML: links to getting started steps
WEB+EXC: update exercises
EXC+ENH: add crossvalidation measure exercise
RF+WEB: add tips and philosophy information
SML: remove trailig whitespace
DOC: add comments to example
DOC: add comments to example
SML: remove trailing whitespace