wusu - wrap and unify sys utils

Some key values, notably in memory and iostat parsers,
are consistent with their corresponding system utilities.
All of them are documented in docstrings of relevant
functions.

NOTE:
dladm(1M), used for interface statistics on Solaris, requires root privileges.

For more information on where wusu gets it's data, user
should consult the following manual pages:

Linux:
 - proc(5)
 - df(1)
 - iostat(1)
 - ip(8)

FreeBSD:
 - clock_gettime(2)
 - df(1)
 - iostat(8)
 - sysctl(8)
 - pstat(8)
 - netstat(1)

SunOS:
 - kstat(1M)
 - swap(1M)
 - df(1M)
 - iostat(1M)
 - dladm(1M)