Split matching and SQL execution

[tleekkul]

At the moment the fostgres.sql view does two things:

1. It pattern matches the URL
2. It executes SQL with numbered parameters ($1 etc.) based on the matched pattern

We should be able to split these.

If we move the match code to fost-web and add the numbered matches as headers in the form __1 etc. then they can be found by a view that only handles the SQL part of the execution and looks for its numbered matches in the headers.

We should disallow nesting of the match view for now. In any case the match will fully consume the path so there won't be anything left.

[KayEss]

If we're doing this then we could also have a re-write view which can set the path by using something that looks like new-path/$1/somewhere/$2/$$with-one-dollar