toplev: Add warning for old kernel version
Basic support for uncore json
Handle variations in input files
Add support for exploding boxes
event_download: Only use argparse if needed

Only use argparse when called from the command line. This avoids
a dependency of ocperf to argparse, making it work again on pre python 2.7
(e.g. RHEL5)
event_download: Better error message when download server not found

Tell the user exactly what to do if the event download did not work.
event_download: Update copyright
toplev: remove unused variable