1) The code was not working correctly with only one k point;
2) In the case of metals the weights wk(ikk) must be used instead
of wg(ikk,ibnd) in sums over k points (courtesy of Tommaso Gorni);
The effect of this bug was small when small smearing was used.
3) The code was not working correctly with ultrasoft pseudopotentials,
because there was a missing term in the external potential due to the
augmentation part (I thank Andrea Dal Corso for helping to solve this problem!).
This problem was not detected before, because I tested the code on Si and Al,
which have small augmentation part, whereas Ag is a good benchmark system.
To this end, I removed the example of Si with USPP and added an example of Ag with USPP.
git-svn-id: http://qeforge.qe-forge.org/svn/q-e/trunk/espresso@11877 c92efa57-630b-4861-b058-cf58834340f0