This is a TODO list, to do not forget things that can be added to this bundle.
They are not sorted by priority:

1) For XC terms, the spin-polarized case is completely absent.
2) There is no treatment of the GGA XC for the non-free BC cases
2b)The gradient of the density is calculated only for free BC
3) The calculation of the kernel for surfaces BC can be cleaned up by hard coding 
   the coefficients of the high order integration (minor change)
3b)The allocations for calculating the surface kernel can be reduced by creating a
   unique workarray for green and green1 in the calculates_green_opt routine
4) Wires