feature: timestamp prefix of `pm2.log`
test cases for timestamp prefix of pm2.log
docs: how to enable timestamp prefix of pm2.log
fix: locale pm2 root dir
fix: travis have no pm2.log but only stdout/stderr
test case: redirect pm2.log
fix: redirect logs before greping
Merge pull request #853 from Tjatse/development

feature: timestamp prefix of `pm2.log`