Merge pull request #72 from ngokevin/master

issue with catching all import errors within hooks
Add stuff for http://travis-ci.org
Merge branch 'master' of github.com:mythmon/wok
Fix requirements.txt
Actually say what tests to run for travis.
Update travis again, but fail less.
Make previews get rendered.
Clean up some files from the sample->test rename.
Convert types to strings, in case they look like numbers.

Fixes #73.
Add textile and markdown2 renderers.

Closes #76.
Fix markdown2 renderer:

* Name should be Markdown2 as that's what the other bit's of code refer 
   to.
* extras need's to be accesed as an attribute of cls

* Driveby fix: Make the Markdown class access it plugins via attribut of cls 
   rather than attribute of Markdown so that if some wants to subclass 
   Markdown, they will be able to overwrite plugins.
Fixes for renderers.

- Textile was referencing markdown.
- cMarkdown isn't actually a drop in replacement, so don't use it.
Add the testing bits for 404 pages.
Update docs about renderers and content.
Don't using logging when importing wok.renders.

Because logging has not been set up yet (because we haven't parsed CLI
options yet) making calls to logging.* will cause logging to be set up
with default values, which is bad.

This is a bad fix. The real fix should be to move parsing of CLI options
to another stage so that we can set up logging before importing the
renders. But that is a bigger change.

ugh ugh ugh ugh ugh ugh ugh.
Add tutorial to the wok site.
Use setuptools.
Fix minor issues

Some of these are just awkward English things. I also fixed "renders"
to "renderers" because it seemed to be "renders" in some places but
"renderers" in others.
Added new demo site to README
Add philip's site to the website too.