don't write out the target if failOnMissing is set and missing files are detected
set grunt.option.force as part of grunt test and add tests for failOnMissing
Merge pull request #1 from jut-io/feature/fail-on-missing-file

enable test for failOnMissing
Merge branch 'feature/fail-on-missing-file'

* feature/fail-on-missing-file:
  set grunt.option.force as part of grunt test and add tests for failOnMissing
  don't write out the target if failOnMissing is set and missing files are detected