...in optional/pldngen.f90 this has to be strongly polished.

+bug fix in that part of the code: The wrong atom type index was used at some places

The bug was introduced in commit 62285e99.

Thanks to Patrick for pointing out that there was a bug.

...as suggested by Bernd + Stefan

...also in this commit: Some minor cleanup

Note: Two changes have been done in global/types.F90:

   1. MERGE(jsp,4,l_noco) -> MERGE(4,jsp,l_noco)
      (I think the new code is correcter. This change is required)

   2. Some dimension variable was replaced by stars%ng2.
      (Maybe this is not required and maybe the previous variable was more correct.)

...also in this commit: global/constants.f -> global/constants.f90

...also in this commit: Replace multiple definitions of lmaxb by a single constant lmaxU_const.

The k point density can now be defined by specifying denX, denY, denZ
parameters in the &kpts line.

Fixes to make pbe faster (again after refactoring of xcpot) Changes for reanabling old CPP_66 functionality

-removing of variable icorr, use of member-functions instead
-removal of icorrkeys module
-removal of hybridmix module
-cleanup at several places