put all the code from _*py3.py modules back where it belongs

[glyph]

The Python 3 port has resulted in a ton of re-shuffling of code into new python-3 only modules. This is a temporary, incremental measure to separate out the stuff that has been ported and tested from the other stuff. Once everything is ported it should be put back.

I don't know if this should be resolved as an individual ticket or once per module or just once as each module's port is complete, so please feel free to close or split up as you feel is appropriate, I'm just filing this so the work doesn't get forgotten; it is a constant annoyance now to find that code which I used to know where it lived has disappeared into some new private module.

[exarkun]

The modules this relates to:

• ./twisted/python/_reflectpy3.py
• ./twisted/python/_utilpy3.py
• ./twisted/internet/_utilspy3.py
• ./twisted/internet/_endpointspy3.py

There should be no more, as that part of the porting process is over.

[exarkun]

Or put another way:

• ./twisted/python/_reflectpy3.py
• ./twisted/python/_utilpy3.py
• ./twisted/internet/_utilspy3.py
• ./twisted/internet/_endpointspy3.py