setup content negotiation for posts

goal was just to get it to fail properly with a ysod. :-]
handle 404 more cleanly

still experimenting
confirm errors still ysod

clean up end request
remove area registration

not using areas
remove global filters

not using them at the moment
add json content negotiation
switch to json.net for json content negotiation
add xml content negotiation
fixed: xml negotiation always on if file exists
add csv content negotiation

works, but the class being written needs to be serializable to csv -
i.e. flat

todo:
work on making the PostViewModel flat
work on providing CSV Formatting through the mediator
use archive action within post view
better printing and pdfs
fix atom link on layout