Removing border from slide images.

The border was driving me nuts because it was too HTML 3.2. But it
may have actually been helping to add some definition to the graphic
information. I'll live with it without the border for a bit and see
what I think.
Removing feedback request; added Twitter handle.

* Feedback request has been expanded in the deck itself, so removing
  it from the wrapper deck.
* More contact information is good. Usually.
Added feedback request; formatting updates to pro-con lists

* Added slide for "what you want to learn".
* Added slide for "what did you actually learn" + fill out the
  conference feedback for the talk.
* Added rant warnings to the commit section.
* Reformatted the pro-con lists on permission strategies to use a
  table.
* Moved descriptions for project hosting notes below diagrams.
* Added sample of each workflow for project hosting section.
* Changed "homework" heading to "so what?"