fully MODULE-ize the fft package


git-svn-id: svn://svn.code.sf.net/p/cp2k/code/trunk@13924 bac0169d-1eea-4375-b5f6-f89d2ced9994
Remove or block out unused variables


git-svn-id: svn://svn.code.sf.net/p/cp2k/code/trunk@13925 bac0169d-1eea-4375-b5f6-f89d2ced9994