Patch 0.21pre6 for 2.4.17

This batch of changes still includes lots of cleanups and code rewrite to make it simpler. Perfomance increase has been noticed too. Comp_cache_free() has been rewritten and does not move fragments to and fro all the time. Vswap does not have functions to lock and unlock its entries since it's not needed. Many other changes in this version and many still to go.

Notes
http://sourceforge.net/project/shownotes.php?release_id=50313

Download
http://prdownloads.sourceforge.net/linuxcompressed/patch-comp-cache-2.4.17-0.21pre6.bz2