Ctor single arg: allow plain object, reject null/undefined

Thank you @kub1x

lib/input.js

@@ -16,6 +16,9 @@ function _createInputDescriptor (input, inputOptions, containerOptions) {
   } else if (is.buffer(input)) {
     // Buffer
     inputDescriptor.buffer = input;
+  } else if (is.plainObject(input) && !is.defined(inputOptions)) {
+    // Plain Object descriptor, e.g. create
+    inputOptions = input;
   } else if (!is.defined(input) && is.object(containerOptions) && containerOptions.allowStream) {
     // Stream
     inputDescriptor.buffer = [];