vmem: vmem_pool_create_in_region() address alignment up to Pagesize

-Update page protection in vmem_pool_create_in_region()
-Update man page
-Update Unit Tests.
The English in this diff doesn't quite make sense.  How about just adding this:

>The
>.I addr
>argument must be page aligned.

Also, please change the version number (near the top of the file) to 0.54 as part of this change.