app: display cpu+mem evt-loop stats
worker: less verbose
Merge pull request #30 from go-hep/dev/mem-stats

Dev/mem stats
doc: update fwk-ex-tuto-1 printouts
all: first stab at a job scripting interface
fwk/job: general support for (de)serialization of job.Stmts
job/stmt: implement Stringer