Have `nonull: true` cause the task to warn and abort.#106

Open

jacksonrayhamilton wants to merge 3 commits intogruntjs:mainfrom

jacksonrayhamilton:master

Commits on Jun 5, 2016

Have `nonull: true` cause the task to fail.
jacksonrayhamilton
committed
Work around process exiting workaround on Node.js 0.10 on Windows.
jacksonrayhamilton
committed
Use throw to emulate exiting more faithfully.
jacksonrayhamilton
committed