Initial commit for view-links-refactor branch.

The motivation behind these changes is the ability to add edit links
that are nested lists.  This allows us to add another dropdown to the
edit bar, from kotti.multilingual.

action_links has disappeared from type_info.  Needs b/w compatiblity.
Also, a usage example.
Work around an issue with our event subscriber, which has problems cleaning things up.
Pin wsgi_intercept to 0.5.1.  This should fix tailing Travis tests.
Add missing dependency to pyramid_chameleon.
Add **kwargs to Node and Content constructors.
Merge branch 'master' into view-links-refactor
I no longer remember why we needed to take care of double event registrations.

But I'm sure it'll pop up soon.  Which is when we'll need to write a test
.
Properly deprecate what was moved from 'kotti.views.util' to 'kotti.util'.
Try to make 'TypeInfo.action_links' a little backward compatible.
Another BBB fix; this time for '(View)Link.path'
Update CHANGES.txt with details for Link/ViewLink changes.
Fix old link in docs.
Fix deprecation warning.
Merge pull request #284 from Kotti/view-links-refactor

Rework implem of 'kotti.util.Link' ('ViewLink') to be more flexible.
Test the TypeInfo.copy method
TypeInfo.copy is a little less shallow now.
Adding third tutorial to the index and fixing the link to it ...
Merge pull request #286 from nightmarebadger/master

Fixing the links to the third tutorial
Fix requirements.txt for pyramid-mako changes

pyramid-mako drops MakoRendererFactoryHelper. pyramid-debugtoolbar 1.0.9 correctly uses the new add_mako_renderer directive.
Merge pull request #287 from davclark/patch-1

Fix requirements.txt for pyramid-mako changes