Added Grunt task funtionality

[akinofftz]

I've added functionality that make bless.js usable as Grunt npm task, see Gruntfile.js.

[dimensia]

Please accept this pull request. Looking for grunt support for bless.

[shindig]

I'd really like to see this also.

[AaronAsAChimp]

I really needed this, so I created a separate repository. https://github.com/Ponginae/grunt-bless

[adam-lynch]

Heads up, I've created a gulp-bless plugin.

[paulyoung]

I'd rather not add things like this as core functionality but think it's great that support for grunt and gulp has been made available by those who know it better and use it more frequently.