title: pyspark: parallelize and collect order preserving
body: <p>For spark in python, do the <code>sc.parallelize()</code> and <code>collect()</code> operations preserve order? 
  For example if I have a list of elements <code>x</code>, will <code>sc.parallelize(x).collect()</code> return a list of elements in the exact same order as <code>x</code>?</p>