merging of Ivan Carmimeo branch with his work on SCDM localization and EXX
Added new developments in EXX + LOCSCDM done by Ivan Carnimeo.
Now it is possible to SCDM localization and perform exact exchange calculations over pairs of localized orbital also with general k_points sums and non only in the gamma case.
still experimental: in the gamma_only case it is possible to perform the scdm localization only once each nscdm steps, for the intermediate steps the rotation of the density matrix is performed via an SVD algorithm
some improvements and cleanup
On top of these changes, in view of the next release the version number is upgraded to 6.4rc and the xml format has been updated to 19.02.07 ( from now on the xml schema versions are numbered with the reverse date notation)