Update Glances with new PsUtil 4.x stats

[nicolargo]

PsUtil 4.0.0 change log: http://grodola.blogspot.fr/2016/02/psutil-4-real-process-memory-and-environ.html

1. Implement "Real" process memory info: USS and PSS (MEM plugin)
2. Memory percent (MEM plugin - TBD)
3. Extended disk IO stats (DISKIO plugin - TBD)

[nicolargo]

Implement "Real" process memory info: USS and PSS (MEM plugin)

replace process MEM% column by USS / PSS ?
=> Not possible because memory_full_info need root right for system processes

>>> psutil.Process(1).memory_full_info()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/psutil/__init__.py", line 997, in memory_full_info
    return self._proc.memory_full_info()
  File "/usr/local/lib/python2.7/dist-packages/psutil/_pslinux.py", line 877, in wrapper
    raise AccessDenied(self.pid, self._name)
psutil.AccessDenied: psutil.AccessDenied (pid=1)

Add new columns ? => Looks great but add to catch the psutil.AccessDenied error for system processes

Other thinks:

• memory_info_ex is deprecated (Measure USS on Linux giampaolo/psutil#744 (comment)). Change it in the processes.py script (__get_extended_stats method). Use memory_full_info() or memory_info() instead.

PsUtil 4.0.0
>>> import psutil
>>> psutil.Process().memory_info()
pmem(rss=9428992, vms=51527680, shared=3870720, text=2867200, lib=0, data=5373952, dirty=0)
>>> psutil.Process().memory_info_ex()
pmem(rss=9437184, vms=51527680, shared=3878912, text=2867200, lib=0, data=5373952, dirty=0)
>>> psutil.Process().memory_full_info()
pfullmem(rss=9441280, vms=51527680, shared=3883008, text=2867200, lib=0, data=5373952, dirty=0, uss=5603328, pss=6246400, swap=0)

• Be carefull to the PsUtit 3.x or lower compatibility.

[nicolargo]

1. memory_info_ex no longer used in the DEVELOP branch.
2. memory_full_info (with USS and PSS stats) used for the extended stats (top process)