library: try to minimize the results types, <PIDS> api

library: try to minimize the results types, <PIDS> api

This is just beginning an effort to minimize/normalize
the sheer variety of results types in use for our API.

In taking these first baby steps, a few anomalies were
found. There'll no doubt be many more yet to discover.

. the _FLT_ (fault) fields were already signed long in
the proc_t (even though their sscanf format used %lu).

. although strtoul will alway return an unsigned long,
all of the _VM_ fields were made signed long just like
other memory fields (& signed sorts more efficiently).

Reference(s):
http://www.freelists.org/post/procps/newlib-drip-drip,4

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