Nonull with src array

[bluee]

nonull does not fail if src is an array of files

Example:

   copy: {
            main: {
                     nonull: true,
                     cwd: '../lib/', 
                     expand: true, 
                     src: csslibfiles, 
                     dest: '../publish/~buildcss', 
                     filter: 'isFile',
                     flatten: true 
            },
        }