core/index: GraceNode should exit with a 'failure' code on error.
Merge pull request #38 from hobein/develop

core/index: GraceNode should exit with a 'failure' code on error.
server module now calculates execution time per request
Merge branch 'develop' of https://github.com/voltrue2/GraceNode into develop
server module fixed start time
removed debug log from server module