added option to append query-like suffix

I am using this to append a file versioning to files for cache-busting
It can be used as static or dynamic in conjunction with gulp-bump/gulp-template

For example

```
<!-- build:js js/lib.js?v=<%= libversion%> -->
..some lib files...
<!-- endbuild -->
<!-- build:js js/app.js?v=<%= appversion%>-->
..some app files...
<!-- endbuild -->
```
will be translated to 

```
    <script src="js/lib.js?v=0.10.6"></script>
    <script src="js/app.js?v=0.7.3"></script>
```

```
var conf = {app: 'app/', dist: 'dist/'};
var pkg = require('./package.json');
gulp.task('usemin-test', function() {
  return gulp.src(conf.app + 'index.html')
  .pipe($('template')(pkg))
  .pipe($('usemin')())
  .pipe(gulp.dest(conf.dist));
});
```