It's dr.
`let` will return 1 when the last expression evaluated results in 0.
Add missing import removed by accident.
Merge pull request #67 from whirm/documentation

Documentation improvements
It's qdel.
Silence pycompile
Use execvpe() instead of call() so we free some unused resources early.
Also, flush stdout/err so we get the output properly sorted.
Make experiment_server.py use gumby.log.
Use prun's exit code instead of -15 when not trapping SIGKILL
Move ColoredFileLogObserver to gumby.log
Increase priority for some sync server messages so they still get show
when not running with DEBUG priority.
Properly split sub-processes output in lines before logging it and buffer
partial lines until new data comes in.
Use new experiment config vars
switch to INFO as log level for the dummy set of experiments
Missed this one
Merge pull request #69 from whirm/further_logging_improvements

Further logging improvements
Update tribler_experiment_setup.sh
Reducing sum_total_records and sum_statistics and using those files when
generating graphs
No more opts used by r graphs
Conflicts:
	scripts/r/statistics.r
Removed dependency on qplot reshape2 and some other obscure r packages.