datapaths: Remove switch.py

We're going to start from scratch here...
openflow: adding a python OpenFlow switch implementation.

Right now it only mimicks the OpenFlow protocol -- it does not
actually route packets. Might be a good start for a full-blown
python implementation for testing purposes within POX though.
switch_impl.py: adding a TODO.

Should really have a of_01-like Task for listening to socket connection
attempts, and creating Connection objects

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extra : transplant_source : Y%F0%B6I%94%7C%96e%9A%24%13%04F%5C%B26w%06%94%90
switch_impl: adding a comment

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extra : transplant_source : pK.Q%85%8E%7B6%2C%88N%A24z%0F%E7%00k%C3o
switch_impl.py: adding a BarrierIn handler

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switch_impl: adding a barrier_in handler

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extra : transplant_source : %ECr/h%9ET%92%97%13_%0B%E3%E0%D7%3DX%AB%87%B5%84
switch_impl.py: enabling ports
switch_impl: Getting rid of (now uneccesary) helper method.
switch_impl.py: Adding a FlowTable.

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extra : transplant_source : %8Ct%3E%1B%89%C7Cw.%E3%E8%9DC%EE%B7%03%89Y%F5%3D
switch_impl: fixing bug in features reply
switch_impl: adding a human-readable name

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extra : transplant_source : %F5%0A%966%89%07M%E2%DFRo%C7%FC%D5%40%C7%AC%E7%1D%24
switch_impl: Fixing a field redefinition bug

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extra : transplant_source : %DFy%98%92y%00tb%19NLf%FB%A3h%25%7F%FE%28%E1
openflow.switch_imply: now uses a separate logger name for each instance

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openflow.switch_impl: adding a method "entries_for_port()" in FlowTable

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extra : transplant_source : %F0%AC%87%28%1F%DBy8%B7%F5_KL%F7%AB%C9%DD%93%E4%60
work commit - need to merge

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openflow.switch_impl: now featuring real packet processing (and a unit test) :)

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extra : transplant_source : %16%FDH%21%24%16%C9%A8%B8%8C%94%D3%CB%3F%9AD%E7p2%0D
switch_imply.py: fixing typoes found by eclipse. + indentation.

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extra : transplant_source : EH%106%D4%B3%C8%2C%964%1E%FD4%3B%40t%02%03%A4P
openflow.switch_impl: fix whitespace, indentation
openflow/topology: fix bug in xid generation that could generate invalid xids

add xid_generator that correctly wraps at 2*32-1
openflow.switch_impl: merge improvements from pox-debugger