Added new option warn_only.
Prevents brunch from returning an error from jshint.
Fixed test to not be a false positive.
jshint would never return undefined for the stuff variable unless the 'undef' option was enabled.
Adds support for reading in a .jshintrc file.
Updated README
Removed error instance var and redundant finally block.
Bugfix, node module dependancy name was incorrect.
Refactored error checking slightly.
Error messages now use throw.
Merge pull request #8 from loadx/warn_with_jshintrc

jshintrc file reading and warn_only option.