Linux: L2Socket can set promiscuous mode (fixes #17)

Return Raw() when an exception occurs in .dispatch_hook()

... if not conf.debug_dissector

Idea from @paaguti in pull request #10.

ls() can now filter by layer name or description

Use list comprehension in diffplot()

Fix for Python 2.5 (cannot mix keyword arguments and **kargs)

Use __slots__ for some Scapy objects

Rename argument / attribute "set"

Add optional parameter plot_xy to .plot() and .multiplot()

Fix automaton tests

Fix IPv6 support on OpenBSD

This way, it is possible with both methods to specify values for the
"x" coordinate. By default, `plot_xy` is False and the "x" coordinate
is the index of the packet in the list.

Examples:

    >>> ans.plot(lambda x: x[1].id)
    >>> ans.plot(lambda x: (x[1].time, x[1].id), plot_xy=True)
    >>> ans.multiplot(lambda x: (x[1][IP].src, x[1].id))
    >>> ans.multiplot(lambda x: (x[1][IP].src, (x[1].time, x[1].id)), plot_xy=True)

Matplotlib support

Use __future__ to allow with statement under Python 2.5

Fix crash when an unpriv user builds an Ether() packet without dst set

Fix layer binding in IGMPv3 (contrib)

When an Ether() / IP() packet is built with IP.dst set and Ether.dst
not set, Scapy tries to fix Ether.dst by sending an ARP request. This
fails when the user cannot send packets.

Before:

    >>> p = str(Ether()/IP(dst="1.2.3.4"))
    Traceback (most recent call last):
      File "<console>", line 1, in <module>
      File "/usr/local/lib/python2.7/dist-packages/scapy/packet.py", line 272, in __str__
        return self.build()
      [...]
      File "/usr/local/lib/python2.7/dist-packages/scapy/arch/linux.py", line 414, in __init__
        self.ins = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, socket.htons(type))
      File "/usr/lib/python2.7/socket.py", line 187, in __init__
        _sock = _realsocket(family, type, proto)
    error: [Errno 1] Operation not permitted

After:

    >>> p = str(Ether()/IP(dst="1.2.3.4"))
    WARNING: Mac address to reach destination not found. Using broadcast.