This example shows how to use pw.x to calculate phonons with a fully 
relativistic US-PP which includes spin-orbit effects.

The calculation proceeds as follows:

1) make a self-consistent calculation for fcc-Pt
   (input=pt.scf_ph.in, output=pt.scf_ph.out).

2) make a phonon calculation at the Gamma point (input=pt.ph.in,
   output=pt.ph.out).

3) make a phonon calculation at X (input=pt.phX.in, output=pt.phX.out).
