Fixed #2

YouTube won't return error, but return `{feed}` anyway, so 
it would throw an exception on the `async.each`. Added a
check for `entry` instead.

Also, because it has no error, the `async.concat` will run
through, so we need to pass an `[]` for it.

Note that due to the asynchronous nature, we have to run
all requests due not not knowing how many videos total.