draft: pyramid 2.0

pyramid 2.0 has been release yesterday, and we need to fix some stuff.

• pyramid.compat as been dropped
• in the cookiejar, the domain is now ".localhost" (I dont understand why, is it what we want ? or is it a bug)
• to actually do the redirect, we need to return the exception, raising the exception crashes the application. I dont see any mention of that in the pyramid's changelog (cf https://docs.pylonsproject.org/projects/pyramid/en/2.0-branch/whatsnew-2.0.html)

related: #272