Config dest possible split files differnt paths

option added to config to allow specifing custom targets

example of usage:

    bowerful: {
        store: 'components',
        dest: 'web/js/vendor',
        destfile: 'vendor',
        customtarget: {
            jquery: 'web/js/vendor/jquery.js'
        },
        packages: {
            jquery: '', 
            underscore: '', 
            backbone: ''
        } 
    }
    
this will concatinate files on vendor.js and also create a file jquery.js.


This will solve issue https://github.com/gyllstromk/grunt-bowerful/issues/5