Added jshint task to grunt script.

Steve,

Here are the changes for just adding the jshint task.  It runs from the command line:
$ grunt jshint

Note that I had to remove the line "grunt.loadNpmTasks("grunt-gpii");" from Gruntfile.js since running the jshint task would fail with:

"Local Npm module "grunt-gpii" not found. Is it installed?
Warning: Task "default" not found. Use --force to continue.

Aborted due to warnings."

I haven't figured out why yet, so it's removed for now.

Next:  trying all the other tasks.