Node version (or tell us if you're using electron or some other framework):

Node version: 4.3.0

ShellJS version (the most recent version/Github branch you see the bug on):

ShellJS version: 0.7.7

Operating system:

Windows 7

Description of the bug:

use cp command copy 2 directory to destination directory
if destination is non-existent, the 2 directory cannot be created correctly

require('shelljs/global');

cp('-r','./src/testA', './dist/');
cp('-r','./src/testB', './dist/');

    |-src
        |-testA
            |-testA.txt
        |-testB
            |-testB.txt

if destination is non-existent, the directory structure is created as follows:

    |-dist
        |-testB
            |-testB.txt
        testA.txt