Polishing the flow contracts

[Stefano Mazzocchi]

One of the major release showstoppers is the lack of confidence on the 
flow contracts.

We cannot release the flow without being confident about its contracts.

And it has been decided to ship the flow with Cocoon 2.1.

So, in order to release, we have to finish polishing the flow.

Things to do are:

1) cleaning up the proper hooks between the flow and the cocoon 
internal. This means adding a flow native object to the Object Model so 
that all cocoon components can have access to it directly (this will 
remove the need for two different velocity generators)

Vadim and Sylvain identified a clean solution for this, can you guys 
please refresh those concepts?

2) polishing the FOM.

                                     - o -

Here is what I would like to see:

 1) no functions without an object namespace. This is to imply that all 
non-prefixed functions belong to the flow. Provides coherent cognitive 
context.

 2) no function duplication. There is only one function that does 
something. [of course, javascript allows you to change those function 
names with your flow, but that's up to the user and doesn't influence 
our contracts[

 3) the following objects:

    flow
    cocoon
    continuation
    log
 4) the following functions

Flow Object:
    flow.import() -> imports another flowscript
Cocoon Object:
    cocoon.sendPage(uri, dict) -> sends a pipeline to the client
    cocoon.sendPageAndWait(uri, dict) -> sends a pipeline to the client 
and save the continuation.

    cocoon.process(uri, dict, output