errstack: first import
error: use errstack
test: fixups for errstack
dflow: use fwk.Errorf. not fmt.Errorf
Merge pull request #27 from go-hep/dev/err-stack

Dev/err stack
make: better 'bench' target
app: restore GOMAXPROCS value after runConcurrent ran
parallel: import from code.google.com/rog-peppe
parallel: fix test import
all: first stab at a job scripting interface
fwk/job: general support for (de)serialization of job.Stmts
job/stmt: implement Stringer