top: refer to memory using strict IEC standard names

top: refer to memory using strict IEC standard names

Admittedly, top referred to memory quantities in
a variety of non-standard ways.  This commit brings
the program and supporting documentation into strict
compliance with IEC standard binary names.

According to wikipedia, as of 2012 this IEC standard
was still not in widespread use.  However, I'm making
this change now for the anal-retentive among us.

Reference:
http://en.wikipedia.org/wiki/Megabyte

Reported by: Roman Mamedov <rm@romanrm.ru>
Bug-Debian:  http://bugs.debian.org/662786

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