Grunt wildcards - st/* - Handle grunt files: per grunt documentation 



We should be able to specify all files in st directory by src: 'st/*'

     googlecharts_exp3: {
        src: ['st/*'],
        output_dir: 'js',
        libraries:[ 'Canvas'],
        jsGlobals: ['google'],
        amd_namespace: 'google-charts-example'
      },

grunt normalizes all src: and files: into Files Array format. This pull attempts to implement that format.