Rudder

Done:
Fuzzy search function taking a token name (&str) and an iterator.
`ast::add_resources()`, if initialisation does not match any declaration
`ast::add_enum_mappings()`, if enum decl name doesn’t match parent decl name
`ast::add_children_list()`, if name not found when trying to define mapping
`enum::add_mapping()`, if an enum value does not match its parent value
`ast::enum()`, if an enum does not match any parent value
`ast::binding_check()`, if a resource type does not exist }
`ast::binding_check()` if a state does not exist for the related resource type
`enum::canonify_expression()` 7 additions

Todo-issues:
Parameter count check is done before binding check. So if a wrong resource type is sent we cannot know it because it will stop at params count if > 0. Maybe reverse the order
This is going on in `enum::fom_pstatement()`

Questions:
When do we enter ast::add_enum_mapping() err ?
How to test enum::canonify_expression, meaning comparisons ?

Applied in changeset rudder|5f3588a94d7e92c20320292b810fafbd6f38ef2a.