README.md: enter a first full description of the suite

This commit just changes the description of the suite to include
pointers to relevant webpages and a first full description of
what it is its purpose.
Add gitignore file

This commit adds a first gitignore to the repository so as to be
able to exclude temporary files generated by editors and have a
clean git status.
Add fio-based test with affinity option

Not being sure whether it's relevant to allow for fio processes to
switch CPU while they're running; adding it here anyway.