Provide per-process getresuid() and getresgid() methods

[GoogleCodeExporter]

This should reflect os.getresuid() [1] and os.getresgid() [2] Python functions 
but in a per-process fashion, and return a named tuple as such:

>>> p = psutil.Process(os.getpid)
>>> p.getresuid()
user(real=1000, effective=1000, saved=1000)
>>> p.getresgid()
group(real=1000, effective=1000, saved=1000)

This should be provided for UNIX systems only and raise AttributeError on 
Windows.

Not sure what to do with current "uid" and "gid" properties.
It probably makes sense to deprecate them.

[1] http://docs.python.org/library/os.html#os.getresuid 
[2] http://docs.python.org/library/os.html#os.getresgid

Original issue reported on code.google.com by g.rodola on 22 Nov 2010 at 12:29

[GoogleCodeExporter]

Implemented on Linux in r835.
I decided to provide this as "uids" and "gids" properties as they're easier to 
type/remember than "getresuid" and "getresgid".

Original comment by g.rodola on 22 Nov 2010 at 1:53

• Added labels: Progress-1in4

[GoogleCodeExporter]

Implemented for FreeBSD in r837.
Re-assigning to Jay for missing OSX implementation.

Original comment by g.rodola on 22 Nov 2010 at 2:45

• Added labels: Progress-2in4
• Removed labels: Progress-1in4

[GoogleCodeExporter]

Implemented on OSX in r916.

Original comment by g.rodola on 17 Feb 2011 at 2:55

• Changed state: FixedInSVN
• Removed labels: Progress-2in4

[GoogleCodeExporter]

Original comment by g.rodola on 20 Mar 2011 at 9:55

• Changed state: Fixed

[GoogleCodeExporter]

[deleted comment]

[GoogleCodeExporter]

Updated csets after the SVN -> Mercurial migration:
r835 == revision 28262c50be27
r837 == revision b5d7376dafd1
r916 == revision 5780f675d6e3

Original comment by g.rodola on 2 Mar 2013 at 11:57