fixes #109 (hopefully)

fixes #108

This is necessary since exec() isn't really a function, and
eval can't evaluate statements.
fixes #104

Fixes #102

Fixes #89 ; Thanks to Nikhil S. Menon for the bug report

Also fixed a few errors like the time it takes to install,
some references to NOX, etc..

Left in noxcore ref, since you can still install it.

Thanks to @xdhanz for the catch, and pull request
closes #84

Reported-by: Julius Bachnick

https://mailman.stanford.edu/pipermail/mininet-discuss/2012-November/001349.html

Reported-by: Julius Bachnick

https://mailman.stanford.edu/pipermail/mininet-discuss/2012-November/001349.html

for OVS

Otherwise, OVS thinks the second controller is a parameter of the first, and
only creates one controller entry as seen in 'ovs-vsctl show'.

Becomes consistent with the OpenFlow walkthrough & MN walkthrough web pages.

No need for this here, especially because this file is in the walkthrough
and will be found by web crawlers.

Was broken in 2.0.0rc1

Reported-by: Julius Bachnick

Source of error: regex to parse ps output had a single space, rather
than handling any amount of whitespace before the CPU percentage.  When
that percentage would drop below 10.0, an space would be printed,
confusing the regex.

Fixed by handling arbitrary whitespace before the percentage.

Conflicts:
	.gitignore
	.pylint
	examples/miniedit.py
	mininet/node.py
	mininet/util.py
	util/install.sh
	util/vm/install-mininet-vm.sh

Also a more complete ping test that parses all output to the CLI.

These tests expand the hifi-specific ones to not just cover whether
a topology can be created with options, but whether those options
are properly implemented within some tolerance, like CPU limits,
link bandwidth, delays, and even drops.

These include dropped pings and iperf hanging.

A number of functions in node.py look like this:
   return self.intf( intf ).<other stuff>

Previously, self.intf(...) in Node would expect a string name for an
interface and return None if an object was passed in instead of a
string name.

Now, be more permissive and assume that objects passed in are for Intf
objects.  This makes all such functions in node.py handle more flexible
input args, either name or actual Intf object.

An alternative and equally valid approach would be to raise an Exception
whenever a non-string, non-falsy value was passed in to Node.intf(), and
to modify the code in at least one place - examples/sshd.py - to pass
the interface name, rather than the interface object.

Also fix input args for examples/scratchnetuser.py - the interface name
was being passed in as the prefix len, which makes no sense.

Prevent idiots like me from getting confused by non-obvious 'broken pipe'
errors when they forget to put 'sudo' in front  :-)

Two benefits:
- One place to change if in the future, a more granular method of
  root access is used (like the BigSwitch patch).
- Makes this reusable by stuff like examples/baresshd.py that use
  the low-level Mininet API.

'mount' shows something slightly different in Ubuntu 12.10:

cgroup on /sys/fs/cgroup type tmpfs (rw,uid=0,gid=0,mode=0755)

Note the lack of a plural on first word cgroup, which has changed.

Still mounted at /sys/fs/cgroup, so check for both possibilities
when instantiated CPU-limited hosts.