Define the filter API #50

Originally reported by: Anonymous

We need to define the full api for the filters. [[br]]
There are two seperate baseobjects, but there is still '''one''' list.

We wanted to change it if i'm not mistaken into two lists.

• One for incoming, (BaseInputFilters)
• and one for outgoing. (BaseOutputFilters)

This would allow for more advanced (but in no case rare) setups.

Futhermore we need to have our api ready to convert all the filters (the longer we wait, the more difficult it will get to change the filters), and to move several other items to filters as well:

• Sessions (it's an option, i know :) )
• CSAuthenticate (as this interferes with any generator based templating filter)
• Caching ?

Moving more features to filters allows the end programmer to have more control, and to decrease the need to patch the server directly. This will make it easier for developers to migrate to CherryPy.

Reported by remco.boerma@gmail.com

• Bitbucket: https://bitbucket.org/cherrypy/cherrypy/issue/50