modelbuilder: extra-warn useless type declaration of attributes

Signed-off-by: Jean Privat <jean@pryen.org>
model: really implement precondition of lookup_first_definition

Signed-off-by: Jean Privat <jean@pryen.org>
typing: `or else` fallback to Object

now you can write

    print "bla: {toto or else "n/a"}"

Signed-off-by: Jean Privat <jean@pryen.org>
tests: add base_orelse2

Signed-off-by: Jean Privat <jean@pryen.org>
phases: remove useless module dependencies

now that the super of nitc is fixed

Signed-off-by: Jean Privat <jean@pryen.org>