64bits update to tango.core.Traits and tango.util.container.Slink

The function staticArraySize now calculates the size of the array from the size of the Element in the array instead of the (*T.ptr) which sometimes seem to be the size of void* in 64bits.

 And the function Slink.nth(int n) is change to Slink.nth(size_t n) which more compatible with 32/64bits system.