Due to popular request: ditch the madvise stuff to 'swap' out tiles, and actually swap them out with munmap. This introduces some complications like memory areas becoming invalid and so. That, and the fact that I did have to change some stuff for this, might cause some fallout. I didn't notice anything strange with it anymore, but please yell if you see odd behaviour or crashes that you can directly link to this commit :-)(This deprecates some functions, I won't remove them because afaik we'd want at least sourcecode compatibility with Krita 1.5. They exist, but _please_ don't use them anymore. To the best of my knowledge, all current occurances are gone, keep it that way :P)