Add zswap backend from Linux kernel 3.11
Update frontswap to Linux kernel 3.11
Update cleancache to Linux kernel 3.11
Update zcache to Linux kernel 3.11
Update zsmalloc to Linux kernel 3.11
Change default VFS cache pressure
Change default swapiness
mm: Rename function "reset_page_mapcount" to "page_mapcount_reset"

In order to accomodate changes from backported (from kernel 3.11) subsystems, this function needs to be renamed.
Adapt to backported frontswap mechanism
Adapt zram to zsmalloc from kernel 3.11