top: exploit new linux-4.5 resident memory enhancement

top: exploit new linux-4.5 resident memory enhancement

Beginning with linux-4.5, the following new fields are
being added under that /proc/<pid>/status pseudo file:
 . RssAnon - size of resident anonymous memory
 . RssFile - size of resident file mappings
 . RssShmem - size of resident shared memory

This patch just represents the initial library and top
support, sharing a commit message with 2 more patches.

p.s. locked resident memory support was also added but
isn't directly related to the kernel 4.5 enhancements.

Reference(s):
commit 1f8e41d01966ef337bc252bffb181d0acc0c8751

Signed-off-by: Jim Warner <james.warner@comcast.net>