Add support for base

[Dremora]

The following piece of code treats app folder as a base, correctly preserving folder structure in dist:

gulp.src(['app/*.coffee', 'app/controllers/**/*.coffee'], {
  base: 'app'
}).pipe(watch(function(files) {
 files.pipe(coffee({bare: true}).on('error', gutil.log))
  .pipe(gulp.dest('dist')));
}));

However, there doesn't seem to be a way to keep this behavior when using glob (I want to keep track of new files):

watch({glob: ['app/*.coffee', 'app/controllers/**/*.coffee'],
  base: 'app'},  // doesn't work
 function(files) {
 files.pipe(coffee({bare: true}).on('error', gutil.log))
  .pipe(gulp.dest('dist')));
});

[floatdrop]

Thanks for pointing that out!