Merge branch 'stable-1.6' into stable-1.7

Makefile

doc/Makefile

doc/daxio/.gitignore

doc/generated/daxio.1

doc/generated/libpmem.7

doc/generated/libpmemblk.7

doc/generated/libpmemlog.7

doc/generated/libpmemobj.7

doc/generated/libpmempool.7

doc/generated/librpmem.7

doc/generated/libvmem.7

doc/generated/libvmmalloc.7

doc/generated/oid_is_null.3

doc/generated/pmem_ctl.5

doc/generated/pmem_flush.3

doc/generated/pmem_is_pmem.3

doc/generated/pmem_memmove_persist.3

doc/generated/pmemblk_bsize.3

doc/generated/pmemblk_create.3

doc/generated/pmemblk_ctl_get.3