Support named file destinations

[stevenbenner]

Right now indent assumes that the dest option is a folder, and will not let users set the destination file name. This should be changed to check if dest is a folder, if it is not a folder then save the result in the exact path that the user specified.

Example:

{
    src: 'path/to/file.js',
    dest: 'path/to/newFile.js'
}